Harrisons Principles of Internal Medicine Self-Assessment and Board Review 18th Ed.

SECTION V. Disorders of the Cardiovascular System

ANSWERS

V-1.  The answer is B. (Chaps. 227, 250) Pulmonary hypertension is associated with a loud second heart sound that is heard to be louder than the first heart sound at the cardiac base. In idiopathic pulmonary arterial hypertension, there is no associated congenital lesion, such as atrial septal defect (ASD). In ASD, the components of the second heart sound, aortic and pulmonic valve closure, do not alter their timing with respect to respiratory cycle and are always widely split, and thus are described as “fixed split.” In idiopathic pulmonary arterial hypertension, the components of the second heart sound are nearly superimposed and loud; often there is little respiratory variation. The soft systolic murmur at the left lower sternal border of tricuspid regurgitation is nearly always present in pulmonary hypertension of all etiologies. Idiopathic pulmonary arterial hypertension, by definition, is not associated with a parenchymal lung disease such as emphysema. Patients with idiopathic pulmonary arterial hypertension should not have physical findings associated with chronic airways disease.

V-2.  The answer is A. (Chap. 227) The patient is very likely to have pericardial tamponade from metastatic cancer as suggested by her elevated neck veins, heart shadow shape and size, and predisposing condition. Because of the exaggerated interventricular dependence, the normal (<10 mmHg) fall in systemic blood pressure with inspiration is exaggerated (often >15 mmHg) with cardiac tamponade. This is referred to as pulsus paradoxus, though it is in fact an augmentation of a normal finding. Kussmaul’s sign, or a lack of fall of the jugular venous pressure with inspiration, usually denotes a lack of compliance in the right ventricle, as seen most frequently in constrictive pericarditis, though it may be found in restrictive cardiomyopathy or massive pulmonary embolism. A rapid y-descent, which follows the peak of the v wave, of jugular venous pressure tracing is indicative of cardiac tamponade. Pulsus parvus et tardus, or small and slow arterial pulsation, is a late finding in aortic stenosis. Late diastolic murmur and opening snap is found in mitral stenosis.

V-3.  The answer is A. (Chap. 227) A fourth heart sound indicates left ventricular presystolic expansion and is common among patients in whom active atrial contraction is important for ventricular filling. A fourth heart sound is not found in atrial fibrillation. An irregular heart rate is characteristic of atrial fibrillation. The irregular rate is often characterized as “irregularly irregular.” A third heart sound occurs during the rapid filling phase of ventricular diastole and indicates heart failure. Reversed splitting of the second heart sound occurs with left bundle branch block, as this patient has. Finally, pulsus alternans is beat-to-beat variability in pulse amplitude. It is present when only every other Korotkoff sound is audible as the cuff pressure is lowered slowly. It is thought to be due to cyclic changes in intracellular calcium and action potential duration and is associated with severe left ventricular failure.

V-4.  The answer is A. (Chap. 227) The presentation of this patient is consistent with the diagnosis of acute valvular dysfunction due to infective endocarditis. The presence of a widened pulse pressure and diastolic murmur heard best along the lower sternal border suggests aortic regurgitation. Panel C of Figure V-4B shows a typical bisferiens pulse that is characteristic of aortic regurgitation. With a bisferiens pulse, there are two distinct pulsations that can be palpated with systole. The initial pulse represents an exaggerated percussion wave reflecting the increased stroke volume that occurs in aortic regurgitation, with the second peak reflecting the tidal, or anacrotic, wave.

Infective endocarditis causes loss of valvular integrity and acutely causes valvular regurgitation. Of the other options, both mitral regurgitation and tricuspid regurgitation (choice E) would cause systolic and not diastolic murmurs. A hyperkinetic pulse may occur in these conditions, particularly if associated with fever or sepsis. With a hyperkinetic pulse the usual dichrotic notch is more pronounced, as seen in panel E of the figure. Mitral stenosis causes a diastolic murmur but is not a common lesion associated with infective endocarditis, unless underlying valvular stenosis was present prior to acquiring the infection. It is not associated with a bisferiens pulse. Aortic stenosis is associated with pulsus parvus et tardus, with a delayed and prolonged carotid upstroke as shown in panel B of the figure. Aortic stenosis has an associated harsh crescendo-decrescendo systolic murmur.

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FIGURE V-4B Schematic diagrams of the configurational changes in carotid pulse and their differential diagnoses. Heart sounds are also illustrated. A. Normal. S4, fourth heart sound; S1, first heart sound; A2, aortic component of second heart sound; P2, pulmonic component of second heart sound. B. Aortic stenosis. Anacrotic pulse with slow upstroke to a reduced peak. C. Bisferiens pulse with two peaks in systole. This pulse is rarely appreciated in patients with severe aortic regurgitation. D. Bisferiens pulse in hypertrophic obstructive cardiomyopathy. There is a rapid upstroke to the first peak (percussion wave) and a slower rise to the second peak (tidal wave). E. Dicrotic pulse with peaks in systole and diastole. This waveform may be seen in patients with sepsis or during intraaortic balloon counter-pulsation with inflation just after the dicrotic notch. [From K Chatterjee, W Parmley (eds): Cardiology: An Illustrated Text/Reference. Philadelphia, JB Lippincott, 1991.]

V-5.  The answer is A. (Chap. 227) Peripheral arterial disease (PAD) affects 5–8% of Americans, with increasing incidence with age. Over the age of 65, the incidence of PAD rises to between 12% and 20%. The primary symptom of PAD is claudication. As this patient describes, claudication occurs with ambulation and is often described as a crampy to aching pain that is relieved with rest. On physical examination, those with PAD often have diminished peripheral pulses, delayed capillary refill, and hair loss in the distal extremities. The skin is often cool to the touch with a thin, shiny appearance. In severe PAD, pain in the extremities occurs at rest. Diagnosis of PAD can be suggested by these findings and should be documented by determination of the ankle-brachial index (ABI), as physical examination alone is insufficient to diagnose PAD. Although lack of a palpable pulse suggests critical ischemia, it is not diagnostic. To perform an ABI, blood pressures are determined in the arm and the lower extremities. Either the dorsalis pedis or posterior tibial pulses can be used. The ABI is calculated by dividing the ankle systolic pressure by the brachial systolic pressure. A resting ABI less than 0.9 is abnormal, but critical ischemia with rest pain does not occur until the ABI is less than 0.3. In individuals with heavily calcified blood vessels, the ABI can be abnormally elevated (ABI >1.2) when PAD is present. In this situation, toe pressures to determine ABI or employing imaging techniques such as MRI or arteriography should be considered. Lower extremity edema is suggestive of congestive heart failure, not PAD.

V-6.  The answer is F. (Chap. 227) When a murmur of uncertain cause is identified on physical examination, a variety of physiologic maneuvers can be used to assist in the elucidation of the cause. Commonly used physiologic maneuvers include change with respiration, Valsalva maneuver, position, and exercise. In hypertrophic cardiomyopathy, there is asymmetric hypertrophy of the interventricular septum, which creates a dynamic outflow obstruction. Maneuvers that decrease left-ventricular filling will cause an increase in the intensity of the murmur, whereas those that increase left-ventricular filling will cause a decrease in the murmur. Of the interventions listed, both standing and a Valsalva maneuver will decrease venous return and subsequently decrease left ventricular filling, resulting in an increase in the loudness of the murmur of hypertrophic cardiomyopathy. Alternatively, squatting will increase venous return and thus decrease the murmur. Maximum handgrip exercise also will result in a decreased loudness of the murmur.

V-7.  The answer is B. (Chap. 228) Left bundle branch, defined by QRS interval greater than 120 milliseconds with typical pattern in V1 and V6, is associated with four conditions: coronary heart disease, hypertensive heart disease, aortic valve disease, and cardiomyopathy. In all cases, the left bundle branch block is associated with increased risk of cardiovascular morbidity and mortality. These conditions share left ventricular pathology. In contrast, right bundle branch block is associated with congenital heart disease, pulmonary vascular disease, and less frequently valvular heart disease.

V-8.  The answer is D. (Chap. 228) The classic findings of hypokalemia are prominent U waves due to prolonged ventricular repolarization. Scooped ST segments are commonly seen with digoxin toxicity. Low P wave amplitude is found in early hyperkalemia. Prolonged QT intervals are often due to drug toxicity such as tricyclic antidepressant overdose, procainamide, quinidine disopyramide, and phenothiazines. Finally, Osborne waves, or convex elevation of the J point, are found in severe hypothermia and are due to repolarization prolongation.

V-9.  The answer is D. (Chaps. 228, 237, and 250) The patient presents from a country with likely low rates of treatment for childhood streptococcal infection and was subsequently at high risk for rheumatic heart disease. Her large pulmonary arteries in the absence of parenchymal infiltrates suggests pulmonary hypertension and her ECG shows right ventricular hypertrophy, characterized by a relatively tall R wave in lead V1, or R greater than or equal to S wave. This is highly likely to be due to mitral stenosis. While aortic stenosis and regurgitation are possible causes, these are less likely. Tricuspid stenosis is not associated with right ventricular hypertrophy. Left ventricular systolic failure may cause pulmonary venous hypertension, but more commonly is associated with evidence of left heart failure on examination.

V-10. The answer is D. (Chaps. 228 and e28) This ECG shows a short ST segment that is most prominent in V2, V3, V4, and V5. Hypercalcemia, by shortening the duration of repolarization, abbreviates the total time from depolarization through repolarization. This is manifested on the surface ECG by a short QT interval. In this scenario, the hypercalcemia is due to the rhabdomyolysis and renal failure. Fluids and a loop diuretic are an appropriate therapy for hypercalcemia. Hemodialysis is seldom indicated. Hemodialysis is indicated for significant hyperkalemia, which may also develop after rhabdomyolysis, manifest by “tenting” of the T waves or widening of the QRS. Classic ECG manifestations of a pulmonary embolus (S1, Q3, T3 pattern) are infrequent in patients with pulmonary embolism (PE), though the changes may be seen with massive PE. There are no signs of myocar-dial ischemia on this ECG, which would make coronary catheterization and 18-lead ECG interpretation of low yield.

V-11. The answer is D. (Chap. 228) Hyperkalemia leads to partial depolarization of cardiac cells. As a result, there is slowing of the upstroke of the action potential as well as reduced duration of repolarization. The T wave becomes peaked, the RS complex widens and may merge with the T wave (giving a sine-wave appearance), and the P wave becomes shallow or disappears. Prominent U waves are associated with hypokalemia; ST-segment prolongation is associated with hypocalcemia.

V-12. The answer is C. (Chaps. 228 and 238) The ECG shows slight right axis deviation and low voltage. These changes are typical of emphysema when the thorax is hyperinflated with air and the flattened diaphragm pulls the heart inferiorly and vertically. An acute central nervous system (CNS) event such as a subarachnoid hemorrhage may cause QT prolongation with deep, wide inverted T waves. Hyperkalemia will cause peaked narrowed T waves or a wide QRS complex. Patients with hypertrophic cardiomyopathy will have left ventricular hypertrophy and widespread deep, broad Q waves.

V-13. The answer is E. (Chaps. 228 and e30) This ECG tracing shows the triad of a short PR interval, wide QRS, and delta waves (seen best in leads I, II, and V5) consistent with Wolff-Parkinson-White (WPW) syndrome. Patients with WPW syndrome are commonly diagnosed asymptomatically when an ECG is performed showing the classic findings. Symptoms are due to conduction via an accessory pathway and include tachypalpitations, lightheadedness, syncope, cardiopulmonary collapse, and sudden cardiac death. Life-threatening presentations are usually due to the development of atrial fibrillation or atrial flutter with 1:1 conduction, both of which can precipitate ventricular fibrillation. Unstable angina is mainly associated with ST-segment abnormalities, although conduction abnormalities may be seen. Pulmonary embolism, which may cause hemoptysis and pleuritic chest pain, has nonspecific ECG findings including S1Q3T3 (acute right ventricular failure) or T-wave abnormalities.

V-14. The answer is E. (Chap. 228) The limb lead aVR generally has a negative deflection, as the primary vector for ventricular depolarization is directed down and away from this lead. Therefore, in the case of left ventricular hypertrophy the negative deflection, or S wave, would be expected to be larger without an effect on the R wave. There are multiple criteria for diagnosing left ventricular hypertrophy on ECG.

V-15. The answer is B. (Chaps. 228 and e30) This ECG tracing shows multifocal atrial tachycardia (MAT), right atrial overload, a superior axis, and poor R-wave progression in the precordial leads. There are varying P-wave morphologies (more than three morphologies) and P-P intervals. MAT is most commonly caused by COPD, but other conditions associated with this arrhythmia include coronary artery disease, congestive heart failure, valvular heart disease, diabetes mellitus, hypokalemia, hypomagnesemia, azotemia, postoperative state, and pulmonary embolism. Anemia, pain, and myocardial ischemia are also causes of tachycardia that should be considered when managing a new tachycardia. These states are usually associated with sinus tachycardia.

V-16. The answer is E. (Chap. 229) Doppler echocardiography uses ultrasound reflecting off moving red blood cells to determine flow velocity within a structure, in this case the heart or great vessels. Thus, it is most useful for determining abnormal flow or flow limitation. Specifically, it is useful in defining valvular regurgitation or stenosis, cardiac output when combined with the cross-sectional area, and diastolic filling of the ventricle. Heart failure with preserved ejection fraction is associated with impaired left ventricle relaxation in early diastole and subsequently there is reduced early transmitral flow compared to normal individuals. Although Doppler might be helpful to determine the physiologic consequence of pericardial effusion, i.e., tamponade, two-dimensional (2D) echocardiography is the preferred mode for effusion diagnosis. Similarly, 2D echocardiography is used to calculate ejection fraction and diagnose cardiac masses. Diagnosis of ischemia can be made with the addition of physiologic or pharmacologic stress to echocardiography, but not with Doppler echocardiography.

V-17. The answer is E. (Chap. 230) Although myocardial infarction, stroke, and death are complications that have been reported with cardiac catheterization (all with a frequency of <0.1%), the more common complications are tachy- or bradyarrhythmias, acute renal failure, and vascular complications. Vascular access site bleeding is the most common complication of cardiac catheterization, occurring in 1.5–2% of patients. When catheterization is performed in an emergent fashion for acute myocardial infarction or for hemodynamically unstable patients, the complication rate may rise substantially.

V-18. The answer is A. (Chap. 230) Although right heart catheterization is no longer routinely performed at the time of left heart catheterization, there remain important indications for this procedure. These include evaluation of unexplained dyspnea, especially when there is a suspicion of pulmonary hypertension; diagnosis of valvular heart disease such as mitral regurgitation; pericardial disease; right and/or left ventricular dysfunction, particularly for determination of severity; diagnosis of congenital heart disease; and suspected intracardiac shunts. In this case, the patient likely has an atrial septal defect with physical examination findings of a loud, fixed split second heart sound and perhaps associated dyspnea. During right heart catheterization, the pulmonary arterial pressures will be measured to assess for pulmonary hypertension, and venous saturation will be measured at the inferior vena cava, right atrium, right ventricle, and pulmonary artery to assess for evidence of an increase in saturation suggestive of intracardiac shunt. All the other patients described would be more appropriately served with a left heart catheterization and coronary angiogram.

V-19. The answer is B. (Chaps. 230 and 250) In the diagnostic algorithm for pulmonary hypertension, the right heart catheterization is important to document the presence and degree of pulmonary hypertension. The right-ventricular systolic pressure (RVSP) on echocardiography provides an estimate of pulmonary arterial pressures, but accurate determination of the RVSP relies on the presence of tricuspid regurgitation and good quality echocardiography. This patient’s body habitus is prohibitive in obtaining good windows for echocardiography. Thus, a right heart catheterization is imperative for documenting pulmonary hypertension, as well as for determining the cause. The right heart catheterization demonstrates an elevated mean arterial pressure, elevated left-ventricular end-diastolic pressure (pulmonary capillary wedge pressure), and elevated mean pulmonary artery pressure. In the presence of a normal cardiac output and an elevated left-ventricular ejection fraction, this is consistent with the diagnosis of diastolic heart failure. Systolic heart failure is associated with similar indices on right heart catheterization, but left-ventricular function is depressed in systolic heart failure. The other causes listed as options are known causes of pulmonary hypertension but would not be expected to cause an increase in the left-ventricular end-diastolic pressure. Obstructive sleep apnea is usually associated only with mild elevations in pulmonary artery pressure. This patient’s BMI puts her at risk for obstructive sleep apnea but would not be responsible for these right heart catheterization values. Both chronic thromboembolic disease and pulmonary arterial hypertension can cause severe elevations in the pulmonary arterial pressure but have a normal left atrial pressure.

V-20. The answer is B. (Chap. 232) The tachycardia-bradycardia variant of sick sinus syndrome is associated with an increased risk of thromboembolism, particularly when similar risk factors are present that increase the risk of thromboembolism in patients with atrial fibrillation. Specific risk factors associated with highest risk include age greater than 65 years and prior history of stroke, valvular heart disease, left ventricular dysfunction, or atrial enlargement. Patients with these risk factors should be treated with anticoagulation.

V-21. The answer is D. (Chap. 232) Bradycardia is frequently present in trained athletes, particularly at night, where heart rates are usually between 40 and 60 beats/min. While sleep apnea can be associated with bradycardia, no apnea was found in this patient on overnight polysomnography. Other possible causes of bradycardia in this patient such as hypothyroidism have been ruled out. Measurement of free T4 is not indicated with a normal TSH. Pacemaker insertion is not indicated for his normal physiology. Carotid sinus massage is likely to cause further bradycardia. Fatigue is likely due to his stressful job.

V-22. The answer is E. (Chap. 232) Sinoatrial dysfunction is often divided into intrinsic disease and extrinsic disease of the node. This is a critical distinction, as extrinsic causes are often reversible and pacemaker placement is not required. Drug toxicity is a common cause of extrinsic, reversible sinoatrial dysfunction, with common culprits including beta blockers, calcium channel blockers, lithium toxicity, narcotics, pentamidine, and clonidine. Hypothyroidism, sleep apnea, hypoxia, hypothermia, and increased intracranial pressure are all reversible forms of extrinsic dysfunction. Radiation therapy can result in permanent dysfunction of the node and therefore is an irreversible, or intrinsic, cause of sinoatrial node dysfunction. In symptomatic patients, pacemaker insertion may be indicated.

V-23. The answer is D. (Chap. 232) When there is evidence of sinoatrial node dysfunction, as manifest in this patient with sinus bradycardia, the first approach is to search for reversible causes. In this case, excessive beta blockade is the most likely explanation for his brady-cardia and symptoms. Stopping the metoprolol at least temporarily is in order. There are no urgent indications for temporary or permanent pacemaker placement, as he does not have a high-level AV block, syncope, or shock. His heart failure should reverse when his heart rate increases. Although pharmacologic chronotropic stimulation can increase heart rate temporarily, his moderate symptoms suggest that simply waiting for the beta blocker to be metabolized will be adequate. There is no evidence of new infarction or post-infarct angina; thus the patient does not require urgent revascularization. Once the patient is stabilized, the risks and benefits of restarting the beta blocker at a lower dosage may be considered.

V-24. The answer is C. (Chap. 232) The patient presents with a classic bulls-eye lesion, or erythema migrans, consistent with Lyme disease. Cardiac conduction abnormalities are common in Lyme disease, often involving the AV node. Temporary pacing may be necessary, but the conduction abnormalities usually resolve. The most common test to diagnose this condition is an ELISA with confirmatory Western blot. Other infectious etiologies can present with heart block such as syphilis and Chagas’ disease, but these would not be associated with the characteristic Lyme rash. Autoimmune and infiltrative diseases may also present with conduction system disease such as ankylosing spondylitis, rheumatoid arthritis, scleroderma, and systemic lupus erythematosus.

V-25. The answer is B. (Chap. 232) Second-degree AV block type 1 (Mobitz type 1) is characterized by a progressive lengthening of the PR interval preceding a pause. The pause in this tracing is between the third and fourth QRS complex. First-degree AV block is a slowing of conduction through the AV junction and is diagnosed when the PR interval is greater than 200 milliseconds. Type 2 second-degree AV block is characterized by intermittent failure of conduction of the P wave without changes in the preceding PR or RR intervals. Second-degree AV block type 2 usually occurs in the distal or infra-His conduction systems.

V-26 and V-27. The answers are B and D, respectively. (Chap. 233) The patient has persistent, non–life-threatening palpitations that distress her enough to seek medical attention. A continuous Holter monitor for 24 hours is appropriate for patients in whom the symptoms happen several times a day in which an event monitor is triggered by the patient when symptoms occur and thus can be worn for a longer period of time. There is no indication of gastrointestinal triggers, so abdominal CT would not be helpful. The atrial premature contractions are uncomplicated, do not require additional diagnostic evaluation at this time, and pose no additional health risk. EP referral is indicated for patients with life-threatening or severe symptoms such as syncope.

V-28. The answer is C. (Chap. 233) The patient has physiologic sinus tachycardia related to a pneumothorax, for which he was at risk from his obstructive lung disease and volume-cycled mechanical ventilation. The increased peak inspiratory pressure on the mechanical ventilator is due to the reduced respiratory system compliance from the pneumothorax. Physiologic sinus tachycardia often comes on slowly and responds poorly to carotid sinus massage with gradual return to original rate. Pharmacologic interventions are usually unsuccessful with correction of the underlying cause required for resolution of the tachycardia. In this case, a tension pneumothorax is confirmed by chest radiograph and, with placement of a chest tube, the tachycardia resolves. Other causes of physiologic sinus tachycardia include pain, hyperthyroidism, anxiety, anemia, hypotension, fever, and exercise.

V-29. The answer is E. (Chap. 233) Patients at the highest risk for stroke associated with atrial fibrillation include those with a prior history of stroke, TIA, or embolism, and patients with hypertension, diabetes mellitus, congestive heart failure, rheumatic heart disease, LV dysfunction, and marked left atrial dilation of greater than 5.0 cm or age greater than 65 years. Anticoagulation should be strongly considered in these patients. Increased left atrial size is a risk factor for chronic atrial fibrillation.

V-30. The answer is B. (Chap. 233) The AFFIRM and RACE trials compared outcomes in survival and thromboembolic events in patients with atrial fibrillation using two treatment strategies: rate control and anticoagulation versus pharmacotherapy to maintain sinus rhythm. There was no difference in events in the two groups, which is thought to be due to the inefficiencies of pharmacotherapy, with over half of patients failing drug therapy, and also the high rates of asymptomatic atrial fibrillation in the sinus rhythm group. Thus, when considering discontinuation of anticoagulation in patients who have maintained sinus rhythm, placing a prolonged ECG monitor is recommended to ensure that asymptomatic atrial fibrillation is not present. Because of the risk of QT prolongation and polymorphic ventricular tachycardia, initiation of dofetilide and sotalol in the hospital is recommended.

V-31. The answer is C. (Chap. 233) The patient has atrial flutter, which has a high risk of thromboembolic events and should be treated the same as atrial fibrillation. If atrial flutter has been present for more than 24–48 hours without anticoagulation, a transesophageal echocardiogram may be performed to rule out left atrial thrombus. If this is not present, cardioversion may be attempted, with anticoagulation continued for 1 month if successful. Transthoracic echocardiography is inadequate to rule out left atrial thrombus. The patient is hemodynamically stable and has no indications for acute cardioversion. Dabigatran is not currently FDA approved for atrial flutter. Intravenous heparin should be started immediately if there are no contraindications, given the greater than 12-hour duration of symptoms.

V-32. The answer is B. (Chap. 233) The ECG shows at least three different P-wave morphologies with three different PR intervals, which is the hallmark of multifocal atrial tachycardia. This is the signature tachycardia of patients with significant pulmonary disease and is commonly seen in patients with chronic obstructive pulmonary disease, as suggested by diffuse polyphonic expiratory wheezing and hyperinflation.

V-33. The answer is D. (Chap. 233) The patient has classic symptoms for an AV nodal reentrant tachycardia. The so-called frog sign (prominent venous pulsations in the neck due to cannon A waves seen in AV dissociation) on physical examination is frequently present and suggests simultaneous atrial and ventricular contraction. First-line therapy for these reentrant narrow complex tachyarrhythmias is carotid sinus massage to increase vagal tone. Often this is all that is required to return the patient to sinus rhythm. If that is not successful, IV adenosine 6–12 mg may be attempted. If adenosine fails, intravenous beta blockers or calcium channel blockers may be used (diltiazem or verapamil). Finally, in hemodynamically compromised patients or those who have failed to respond to previous measures, DC cardioversion with 100–200 J is indicated.

V-34. The answer is D. (Chap. 233) The patient has an accessory conduction pathway, as evidenced by the delta waves on his baseline ECG. He now presents with atrial fibrillation through the accessory pathway. The wide complex is not due to ventricular arrhythmia but rather the aberrant accessory conduction through the accessory pathway. In general, this reentrant tachycardia may be treated as all others, with the exception of avoiding digoxin and verapamil, both of which may cause deterioration to ventricular fibrillation. Digoxin is thought to shorten the refractory period of the accessory pathway and thus can precipitate degeneration to ventricular fibrillation. Verapamil is thought to cause systemic vasodilation, with a resultant increase in sympathetic tone, and thus may precipitate ventricular fibrillation as well.

V-35. The answer is A. (Chap. 233) Atrial-ventricular dissociation is a classic finding in ventricular tachycardia. Physical examination may show jugular vein cannon A waves when the atria contracts against a closed tricuspid valve and the ECG will manifest this with atrial capture and/or fusion beats. Other findings on ECG of ventricular tachycardia include QRS duration greater than 140 milliseconds for right bundle branch pattern in V1 or greater than 160 milliseconds for left bundle morphology in lead V1, frontal plane axis of –90 to 180°, delayed activation during initial phase of the QRS complex, or bizarre QRS pattern that does not mimic typical right or left bundle branch block QRS complex patterns. An irregularly irregular rhythm with changing QRS complexes suggests atrial fibrillation with ventricular preexcitation. Carotid sinus massage, aimed at increasing vagal tone and slowing AV node conduction, is not effective at slowing ventricular tachycardia because the reentrant focus is below the AV node.

V-36 and V-37. The answers are C and C, respectively. (Chap. 233) The patient’s rhythm is torsade de pointes, with polymorphic ventricular tachycardia and QRS complexes with variations in amplitude and cycle length, giving the appearance of oscillation about an axis. Torsades de pointes are associated with a prolonged QT interval; thus, anything that is associated with a prolonged QT can potentially cause torsade. Most commonly, electrolyte disturbances such as hypokalemia and hypomagnesemia, phenothiazines, fluoroquinolones, antiarrhythmic drugs, tricyclic antidepressants, intracranial events, and bradyarrhythmias are associated with this malignant arrhythmia. Management, besides stabilization, which may require electrical cardioversion, consists of removing the offending agent. In addition, success in rhythm termination or prevention has been reported with the administration of magnesium as well as overdrive atrial or ventricular pacing, which will shorten the QT interval. Beta blockers are indicated for patients with congenital long QT syndrome, but are not indicated in this patient.

V-38. The answer is C. (Chap. 233) There are three main mechanisms by which arrhythmias are initiated and maintained: automaticity, afterdepolarizations, and reentry. Automaticity, such as that seen with sinus tachycardia, atrial premature complexes, and some atrial tachycardias, is due to an increase in the slope of phase 4 of the action potential. The depolarization threshold is reached more quickly and repeatedly. Afterdepolarizations are associated with an increase in cellular calcium accumulation, leading to repeated myocar-dial depolarization during phase 3 (early) and phase 4 (delayed) of the action potential. Early afterdepolarizations may be related to the initiation of torsades de pointes. Delayed afterdepolarizations are responsible for arrhythmias related to digoxin toxicity and for catecholamine-induced ventricular tachycardia. Reentry is due to inhomogeneities in myocardial conduction and refractory periods. With reentry, conduction is blocked in one pathway, allowing slow conduction in the other. This allows for sufficient delay so that the blocked site has time for reentry and propagation of the tachycardia within the two pathways. Reentry appears to be the mechanism for most supraventricular and ventricular tachycardias.

V-39. The answer is C. (Chap. 233) The mechanisms for atrial fibrillation initiation and maintenance are still debated; however, there are anatomic structures that play a role in both of these processes. Muscularized tissue at the orifices of the pulmonary vein inlets are the predominant anatomic drivers of atrial fibrillation, although metabolic disturbances (e.g., hyperthyroidism, inflammation, infection) are also very common. Radiofrequency ablation of the tissue in the area of the pulmonary vein inlets can terminate atrial fibrillation; however, recurrences are not uncommon and other anatomic drivers may be present. The left atrial appendage is an important site of thrombus formation in patients with atrial fibrillation. Any focus within the left or right atrium can be a focus of reentry of focal atrial tachycardia, including the mitral annulus or sinus venosus. Increased automaticity of the sinus node is the mechanism for sinus tachycardia.

V-40. The answer is B. (Chap. 233) Symptoms of atrial fibrillation vary dramatically. The most common symptom is tachypalpitations; however, the hemodynamic effects account for symptoms of impaired left ventricular filling. In atrial fibrillation, there is not an effective atrial contraction to augment late-diastolic left ventricular filling. In patients with impaired ventricular diastolic function, this loss of effective atrial contraction causes impaired left ventricular filling, increased left atrial filling pressures, and pulmonary congestion. These hemodynamic effects are more common in the elderly and in patients with long-standing hypertension, hypertrophic cardiomyopathy, and obstructive aortic valve disease. The tachycardia of atrial fibrillation further compromises left ventricular filling and increases atrial filling pressures. Atrial fibrillation may occur with acute alcohol intoxication, with warming of hypothermic patients, and postoperatively after thoracic surgery. The magnitude of the hemodynamic effect and symptoms will be related to ventricular rate (a slower rate allows more time for left ventricular filling) and underlying cardiac function.

V-41. The answer is E. (Chap. 234) The patient presents with evidence of heart failure by history, and physical examination confirms this diagnosis. Physical examination also shows exophthalmos and a fine tremor, which are suggestive of hyperthyroidism. Thyrotoxicosis, along with anemia, nutritional disorders, and systemic arteriovenous shunting, can all cause high-output heart failure. Although systolic and diastolic dysfunction are more common causes of heart failure, disorders associated with a high-output state are often reversible, and therefore a diagnosis should be pursued when clinical clues suggest this may be present.

V-42. The answer is C. (Chap. 234) Circulating levels of natriuretic peptides may be a useful adjunctive tool in the diagnosis of heart failure, but they cannot replace clinical judgment. BNP or N-terminal BNP are most commonly used and are released from the failing heart, though their release is not specific to left or right heart failure; thus, elevations are commonly seen in cor pulmonale associated with pulmonary vascular disease as well as in patients with left heart failure. Additionally, there are a number of factors that may affect the level of BNP that is normally released from the failing heart. Age and renal dysfunction increase plasma BNP levels. Obesity is associated with falsely low BNP levels. Although BNP levels may normalize after therapy, serial monitoring of this peptide is not presently recommended as a guide for heart failure therapy.

V-43. The answer is E. (Chap. 234) Several drugs have been shown to prevent disease progression in heart failure including ACE inhibitors, angiotensin receptor blockers, beta blockers, and aldosterone antagonists. ACE inhibition has been shown to improve symptoms and survival, reduce cardiac hypertrophy, and reduce hospitalizations. Its use is often complicated by cough related to kinin potentiation, which is an acceptable reason to switch to an angiotensin receptor blocker. Digoxin therapy has not been shown to improve survival, may be associated with dose toxicity, and in patients with stable disease who are not frequently hospitalized, can usually be withdrawn. Beta blocker therapy may occasionally be associated with worsening heart failure symptoms at the time of initiation, but this can usually be managed with increased diuretics. The benefits of beta blockers would far outweigh the nuisance of occasional extra diuretics in this patient. Aldosterone antagonists such as spironolactone and eplerenone are recommended for patients with EF less than 35% who are receiving standard therapy as above. There is no known benefit to one member of this class of drugs over another.

V-44. The answer is E. (Chap. 234) Although there is a wealth of information on which drugs will improve symptoms and survival in heart failure with reduced ejection fraction, little is known about heart failure with preserved ejection fraction. In fact, there are no proven or approved pharmacologic therapies for patients with heart failure and preserved ejection fraction. Therapy should be aimed at treating the predisposing factors for development of this condition, i.e., treat systemic hypertension if present, reverse ischemia if appropriate, etc. Precipitating factors, such as dietary indiscretion in this patient, atrial fibrillation, or infection, may be addressed to improve symptoms. Sildenafil is currently only approved for therapy of pulmonary arterial hypertension and is not proven to be useful for pulmonary hypertension associated with heart failure with preserved ejection fraction.

V-45. The answer is C. (Chap. 234) The New York Heart Association (NYHA) classification is a tool to define criteria that describe the functional ability and clinical manifestations of patients in heart failure. It is also used in patients with pulmonary hypertension. These criteria have been shown to have prognostic value with worsening survival as class increases. They are also useful to clinicians when reading studies to understand the entry and exclusion criteria of large clinical trials. Class I is used for patients with no limiting symptoms; class II for patients with slight or mild limitation; class III implies no symptoms at rest but dyspnea or angina or palpitations with little exertion—patients are moderately limited; class IV is used for severely limited patients in whom even minimal activity causes symptoms. Treatment guidelines also frequently base recommendations on these clinical stages. This patient has symptoms with mild exertion but is comfortable at rest; therefore, he is NYHA class III.

V-46. The answer is B. (Chap. 234) Patients with severe congestive heart failure often exhibit Cheyne-Stokes breathing, defined as intercurrent short periods of hypoventilation and hyperventilation. The mechanism is thought to relate to the prolonged circulation time between the lungs and the respiratory control centers in the brain, leading to poor respiratory control of PaCO2. The degree of Cheyne-Stokes breathing is related to the severity of heart failure. This pattern of breathing is different from obstructive sleep apnea, which is notable for loud snoring, periods of apnea, and sudden waking. Patients are also often hypersomnolent during the day. While sleep apnea is managed with weight loss and overnight CPAP, Cheyne-Stokes breathing is difficult to address as it is often a sign of advanced systolic dysfunction and implies a poor prognosis. All efforts to further maximize heart failure management are indicated. A sleep study would demonstrate this pattern of breathing, but this history and clinical presentation is typical. There is no role for bronchodilators or an electroencephalogram.

V-47. The answer is B. (Chap. 235) Coronary artery disease is a common late complication after cardiac transplantation and is thought to be due to a primary immunologic injury of the vascular endothelium, though it is influenced by nonimmunologic factors such as dyslipidemia, diabetes mellitus, and cytomegalovirus infection. Use of mycophenolate mofetil and the mammalian target of rapamycin sirolimus have been associated with a lower short-term incidence of coronary intimal thickening. Similarly, statin use has been shown to reduce the incidence of this complication. Because donors are generally young, the coronary artery disease after transplantation is not thought to be due to coronary lesions present pretransplantation.

V-48. The answer is E. (Chap. 234) Ventricular assist device therapy can be used either as a “bridge” to transplantation in eligible candidates or as a final destination in patients with end-stage heart failure who are not transplant candidates. There are four FDA-approved devices, all of which share common complications including thromboembolism, cerebrovascular accident, device failure, and infection.

V-49. The answer is E. (Chap. 236) Atrial septal defect (ASD) is a not uncommon simple congenital heart disease lesion that is often diagnosed in adults. Because of chronic left-to-right shunting of intracardiac blood, pulmonary arterial hypertension is a well-recognized common complication. With the development of pulmonary arterial hypertension, the potential for paradoxical embolization of either air or thrombotic material from the right atrium to the systemic circulation is increased. Similarly, with exertion in the context of pulmonary arterial hypertension and ASD, blood may shunt right to left, leading to systemic arterial oxygen desaturation. Atrial fibrillation or other supraventricular arrhythmias may occur, also as a result of atrial stretching with the lesion. While atherosclerosis and unstable angina may certainly occur in adults, is not a reported complication of ASD.

V-50. The answer is D. (Chap. 236) The patient has secondary erythrocytosis due to Eisenmenger’s syndrome and chronic arterial hypoxemia. Her partially corrected left-to-right shunt resulted in chronic pulmonary circulation overflow and the subsequent development of pulmonary arterial hypertension. With a rise in pulmonary vascular pressure, the shunt reverses to become predominantly right to left, which causes systemic oxygen desaturation. Because hypoxemia is caused by shunt and not ventilation/perfusion mismatch (as in typical COPD), it is not responsive to oxygen therapy. Peripheral desaturation results in decreased oxygen delivery to the kidneys, increased erythropoietin secretion, and resultant erythrocytosis. Erythropoietin levels would be expected to be elevated in this case (in contrast to polycythemia vera rubra). Phlebotomy is only used for patients with symptomatic erythrocytosis; hyperviscosity symptoms, including neurologic symptoms such as transient ischemic attack; epistaxis or bleeding symptoms; or visual changes. Because iron depletion may worsen viscosity even at a lower hematocrit, it is considered as only a temporary therapy for management of erythrocytosis in Eisenmenger’s syndrome. This patient had no symptoms referable to erythrocytosis; therefore, expectant management is most appropriate.

V-51. The answer is D. (Chap. 236) Routine antibiotic prophylaxis is indicated for bacteremic dental procedures or instrumentation through an infected site in most patients with operated congenital heart disease, particularly whenever foreign material is present. The one exception is patches that don’t have a post-placement high-grade leak, where prophylaxis is only required for 6 months until endothelialization.

V-52. The answer is E. (Chap. 236) The patient presents with dextrocardia on his chest radiograph and situs inversus, or complete mirror image situs inversus on examination. When dextrocardia occurs in isolation without situs inversus, multiple cardiac abnormalities are frequently present. Alternatively, when dextrocardia occurs with situs inversus, other cardiac defects are unlikely. Kartagener’s syndrome with mucociliary dysfunction may underlie situs inversus, but it is associated with sinusitis and chronic bronchitis, which this patient did not have.

V-53 and V-54. The answers are C and A, respectively. (Chap. 236) This patient has a coarctation of the aorta presenting with marked hypertension proximal to the lesion. The narrowing most commonly occurs distal to the origin of the left subclavian artery, explaining the equal pressure in the arms and reduced pressure in the legs. Coarctations account for approximately 7% of congenital cardiac abnormalities, occur more frequently (2×) in men than in women, and are associated with gonadal dysgenesis and bicuspid aortic valves. Adults will present with hypertension, manifestations of hypertension in the upper body (headache, epistaxis), or leg claudication. Physical examination reveals diminished and/or delayed lower extremity pulses, enlarged collateral vessels in the upper body, or reduced development of the lower extremities. Cardiac examination may reveal findings consistent with left ventricular (LV) hypertrophy. There may be no murmur, a midsystolic murmur over the anterior chest and back, or an aortic murmur with a bicuspid valve. Transthoracic (suprasternal/parasternal) or transesophageal echocardiography, contrast CT or MRI of the thorax, or cardiac catheterization can be diagnostic. MRI of the head would not be useful diagnostically. The clinical picture is not consistent with renal artery stenosis, pheochromocytoma, carcinoid, or Cushing’s syndrome.

V-55. The answer is E. (Chap. 237) Mitral stenosis is one of the leading causes of pulmonary hypertension worldwide, particularly in developing countries where the treatment of streptococcal disease is less available. The primary determinants of pulmonary artery pressure are left atrial pressure, pulmonary vascular resistance, and flow. Mitral stenosis may restrict flow from the left atrium to the left ventricle, and thus is associated with left atrial hypertension and passive pulmonary hypertension (due to back pressure). Additionally, the pulmonary vascular bed may actively vasoconstrict in response to left atrial hypertension. Additional contributors to pulmonary hypertension in mitral stenosis include interstitial edema in the walls of small pulmonary vessels and, in end-stage disease, obliterative changes in the pulmonary vascular bed as may be seen in some forms of pulmonary arterial hypertension. Pulmonary hypertension related to mitral stenosis is generally reversible with correction of the valvular lesion.

V-56 and V-57. The answers are A and E, respectively. (Chap. 237) The patient presents with a relatively stable ST elevation myocardial infarction. He likely has extensive necrosis given the duration of symptoms and ECG findings, and thus is at risk for complication of myocardial infarction. In this case, his acute dyspnea, worsening oxygenation, and asymmetric edema on chest radiograph all point to acute mitral regurgitation from papillary muscle rupture. An allergic reaction to a medication should not cause severe hypoxemia. It may cause rather mild reversible hypoxemia, and should not cause an abnormal chest radiograph. The classic finding of acute mitral regurgitation is a relatively loud systolic murmur heard best at the apex and radiating to the axilla. The murmur is described as having a “cooing” or “seagull-like” quality. A fourth heart sound is also common. Management of acute mitral regurgitation includes afterload and preload reduction, if possible, often with intravenous nitroprusside. If patients are unable to tolerate medical interventions to achieve this because of systemic hypotension, as in this patient, an intraaortic balloon pump is indicated. Albuterol and methylprednisolone are indicated for acute bronchospasm due to primary airways disease, but would not be helpful for the management of cardiogenic shock.

V-58. The answer is C. (Chap. 237) The patient has classic physical examination findings for mitral valve prolapse with a midsystolic click that may or may not be associated with a systolic murmur. Mitral valve prolapse is generally thought to be a benign lesion, with most patients never developing symptoms during their lifetimes. While many patients with heritable connective tissue disorders such as Marfan’s syndrome have mitral valve prolapse, in the majority of cases, a cause is not identified. Mitral valve prolapse may be seen on echocardiography by systolic displacement of the mitral valve leaflets by at least 2 mm into the left atrium. Doppler imaging may also be helpful to define the condition. Because the lesion is generally benign, endocarditis prophylaxis is generally not indicated unless the patient has a prior history of endocarditis. Although some patients develop atrial arrhythmias in conjunction with mitral valve prolapse, prophylactic antiplatelet agents or warfarin are not recommended, as most patients do not have complications.

V-59. The answer is B. (Chap. 237) The patient has aortic stenosis that presented late in life. While bicuspid aortic valve underlies nearly half of all aortic stenosis cases, this lesion typically presents earlier in life, and only 40% of patients greater than 70 years old with aortic stenosis who undergo surgery have a bicuspid valve. Rheumatic heart disease may cause aortic stenosis, but almost invariably mitral stenosis is also present. Underlying connective tissue disease is not known to be associated. Modern research on the development of aortic stenosis has shown that several traditional atherosclerotic risk factors are present such as diabetes mellitus, smoking, chronic kidney disease, and the metabolic syndrome. Polymorphisms of the vitamin D receptor have also been demonstrated in patients with symptomatic aortic stenosis.

V-60. The answer is C. (Chap. 237) Exertional syncope is a late finding in aortic stenosis (AS) and portends a poor prognosis. Patients with this symptom or with angina pectoris have an average time to death of 3 years. Patients with dyspnea have 2 years, and patients with heart failure have an average time to death of 1.5–2 years. Because of these data, patients with severe AS and symptoms should be strongly considered for surgical therapy.

V-61. The answer is A. (Chap. 237) Patients with severe aortic regurgitation will have a “water-hammer” pulse that collapses suddenly as arterial pressure rapidly falls during late systole and diastole, a so-called Corrigan’s pulse. Capillary pulsations seen in the nail bed in severe aortic regurgitation are named Quincke’s pulse. Traube’s sign, or a pistol shot sound, may be heard over the femoral arteries and Duroziez’s sign, with a to-and-fro murmur over the femoral artery, have also been described. Pulsus parvus et tardus is found in severe aortic stenosis. Pulsus bigeminus occurs when there is a shorter interval after a normal beat with a following low volume pulse, often with a premature ventricular beat. Pulsus paradoxus has been described with pericardial tamponade or severe obstructive lung disease. Pulsus alternans is alternating large and small volume pulses seen in severe heart failure.

V-62 and V-63. The answers are C and C, respectively. (Chap. 237) The patient presents with heart failure during her second trimester from a region with high rates of rheumatic fever. She is therefore at risk for rheumatic mitral stenosis, which often presents during the second trimester of pregnancy as the cardiac output must rise to accommodate the fetus and intravascular volume expands substantially. The stenotic valve cannot accommodate the increased flow demands of pregnancy, and congestive heart failure ensues with secondary pulmonary venous hypertension. The patient has evidence of heart failure on examination with pulmonary hypertension. Her diastolic rumble is characteristic of mitral stenosis. Finally, hemoptysis is a not infrequent finding in severe mitral stenosis and may be due to the rupture of pulmonary-bronchial venous connections secondary to pulmonary venous hypertension. Occasionally, pink frothy sputum can be found in patients with frank alveolar hemorrhage related to elevated pulmonary capillary pressure. Mitral stenosis is readily demonstrated by echocardiography. While right heart catheterization may demonstrate pulmonary hypertension and an elevated pulmonary capillary wedge pressure, the etiology of these findings will remain unknown without imaging of the left heart. Short-term management of mitral stenosis with heart failure should include diuretics. As the patient does not have left ventricular failure, ACE inhibition and digoxin are not likely to alleviate her symptoms. Occasionally, beta blockade may improve symptoms, particularly in patients with symptomatic atrial arrhythmias. Anticoagulation is not indicated in mitral stenosis alone unless atrial arrhythmias or pulmonary embolism is present. As infection does not underlie the patient’s hemoptysis, further antibiotics will not be helpful.

V-64. The answer is D. (Chap. 237) Indications for surgical repair of mitral regurgitation are dependent on left-ventricular function, ventricular size, and the presence of sequelae of chronic mitral regurgitation. The experience of the surgeon and the likelihood of successful mitral valve repair are also important considerations. The management strategy for chronic severe mitral regurgitation depends on the presence of symptoms, left-ventricular function, left-ventricular dimensions, and the presence of complicating factors such as pulmonary hypertension and atrial fibrillation. With very depressed left-ventricular function (<30% or end-systolic dimension >55 mm), the risk of surgery increases, left-ventricular recovery is often incomplete, and long-term survival is reduced. However, since medical therapy offers little for these patients, surgical repair should be considered if there is a high likelihood of success (>90%). When ejection fraction is between 30% and 60%, and end-systolic dimension rises above 40 mm, surgical repair is indicated even in the absence of symptoms, owing to the excellent long-term results achieved in this group. Waiting for worsening left-ventricular function leads to irreversible left-ventricular remodeling. Pulmonary hypertension and atrial fibrillation are important to consider as markers for worsening regurgitation. For asymptomatic patients with normal left-ventricular function and dimensions, the presence of new pulmonary hypertension or atrial fibrillation in patients with normal ejection fraction and end-systolic dimensions are class IIa indications for mitral valve repair.

V-65. The answer is F. (Chap. 237) Tricuspid regurgitation is most commonly caused by dilation of the tricuspid annulus due to right-ventricular enlargement of any cause. Any cause of left-ventricular failure that results in right-ventricular failure may lead to tricuspid regurgitation. Congenital heart diseases or pulmonary arterial hypertension leading to right-ventricular failure will dilate the tricuspid annulus. Inferior wall infarction may involve the right ventricle. Rheumatic heart disease may involve the tricuspid valve, although less commonly than the mitral valve. Infective endocarditis, particularly in IV drug users, will infect the tricuspid valve, causing vegetations and regurgitation. Other causes of tricuspid regurgitation include carcinoid heart disease, endomyocardial fibrosis, congenital defects of the atrioventricular canal, and right-ventricular pacemakers.

V-66. The answer is A. (Chap. 237) Bioprosthetic valves are made from human, porcine, or bovine tissue. The major advantage of a bioprosthetic valve is the low incidence of thromboembolic phenomena, particularly 3 months after implantation. Although in the immediate postoperative period some anticoagulation may occur, after 3 months there is no further need for anticoagulation or monitoring. The downside is the natural history and longevity of the bioprosthetic valve. Bioprosthetic valves tend to degenerate mechanically. Approximately 50% will need replacement at 15 years. Therefore, these valves are useful in patients with contraindications to anticoagulation, such as elderly patients with comorbidities and younger patients who desire to become pregnant. Elderly people may also be spared the need for repeat surgery, as their life span may be shorter than the natural history of the bioprosthesis. Mechanical valves offer superior durability. Hemodynamic parameters are improved with double-disk valves compared with single-disk or ball-and-chain valves. However, thrombogenicity is high and chronic anticoagulation is mandatory. Younger patients with no contraindications to anticoagulation may be better served by mechanical valve replacement.

V-67. The answer is E. (Chap. 238) Many infectious etiologies have been associated with the development of inflammatory myocarditis including viral agents (coxsackie, adenovirus, HIV, hepatitis C) and parasitic agents, with Chagas disease or T. cruzi being most prominent, but also toxoplasmosis. Additionally, bacterial etiologies like diphtheria, spirochetal disease like Borrelia burgdorferi, rickettsial disease, and fungal infections have been associated.

V-68. The answer is C. (Chap. 238) Peripartum cardiomyopathy is a rare complication of pregnancy and can occur during the last trimester or within the first 6 months postpartum. Risk factors include advanced age, increased parity, twin pregnancy, malnutrition, use of tocolytic therapy for premature labor, and preeclampsia.

V-69. The answer is A. (Chap. 238) Beriberi heart disease is a dilated cardiomyopathy due to thiamine deficiency. While uncommon in developed countries, this condition still occurs in patients who derive most of their calories from alcohol and has been reported in teenagers who eat only highly processed foods. This condition involves systemic vasodilation with a very high cardiac output in its early stages. In advanced disease, a low-output state can occur. Thiamine repletion can lead to a complete recovery. Patient A has evidence of heart failure with systemic vasodilation and elevated cardiac output, as would be found in beriberi. Alternatively, patient B has normal hemodynamics. Patient C has evidence of low-output heart failure with systemic vasoconstriction. Patient D has elevated pulmonary arterial pressures with right heart failure in conjunction with normal pulmonary capillary wedge pressure, consistent with primary pulmonary vascular disease, e.g., pulmonary arterial hypertension. Patient E has low right heart filling pressures, with somewhat low cardiac output and elevated systemic vascular resistance, as might be found in hypovolemic shock.

V-70. The answer is E. (Chap. 238) Hypertrophic cardiomyopathy usually presents between age 20 and 40 years, with the most common symptom being dyspnea. Many patients are, however, asymptomatic and the only clue to the presence of this potentially deadly disease is physical examination. Physical examination will show a harsh systolic murmur heard best at the left lower sternal border arising from both the outflow tract turbulence during ventricular ejection and the often concomitant mitral regurgitation. Maneuvers that decrease ventricular volume such as Valsalva or moving from squatting to standing will enhance the murmur. Conversely, maneuvers that increase left ventricular volume will decrease the murmur’s intensity. These include hand grip and squatting. Having the patient lie with the left side down and leaning forward may make the friction rub of pericarditis more audible.

V-71. The answer is E. (Chap. 238) A common diagnostic dilemma is differentiating constrictive pericarditis from a restrictive cardiomyopathy. Elevated jugular venous pressure is almost universally present in both. Kussmaul’s sign (increase or no change in jugular venous pressure with inspiration) can be seen in both conditions. Other signs of heart failure do not reliably distinguish the two conditions. In restrictive cardiomyopathy, the apical impulse is usually easier to palpate than in constrictive pericarditis, and mitral regurgitation is more common. These clinical signs, however, are not reliable to differentiate the two entities. In conjunction with clinical information and additional imaging studies of the left ventricle and pericardium, certain pathognomic findings increase diagnostic certainty. A thickened or calcified pericardium increases the likelihood of constrictive pericarditis. Conduction abnormalities are more common in infiltrating diseases of the myocardium. In constrictive pericarditis, measurements of diastolic pressures will show equilibrium between the ventricles, while unequal pressures and/or isolated elevated left ventricular pressures are more consistent with restrictive cardiomyopathy. The classic “square root sign” during right heart catheterization (deep, sharp drop in right ventricular pressure in early diastole, followed by a plateau during which there is no further increase in right ventricular pressure) can be seen in both restrictive cardiomyopathy and constrictive pericarditis. The presence of a paraprotein abnormality (MGUS, myeloma, amyloid) makes restrictive cardiomyopathy more common.

V-72. The answer is D. (Chap. 238) Cardiac involvement is common in many of the neuromuscular diseases. The ECG pattern of Duchenne’s muscular dystrophy is unique and consists of tall R waves in the right precordial leads with an R/S ratio greater than 1.0, often with deep Q waves in the limb and precordial leads. These patients often have a variety of supraventricular and ventricular arrhythmias, and are at risk for sudden death due to the intrinsic cardiomyopathy as well as the low ejection fraction. Implantable cardioverter defibrillators should be considered in the appropriate patient. Global left ventricular dysfunction is a common finding in dilated cardiomyopathies, whereas focal wall motion abnormalities and angina are more common if there is ischemic myocardium. This patient is at risk for venous thromboembolism; however, chronic thromboembolism would not account for the severity of the left heart failure and would present with findings consistent with pulmonary hypertension. Amyotrophic lateral sclerosis is a disease of motor neurons and does not involve the heart. This patient would be young for that diagnosis. An advanced atrial septal defect would present with cyanosis and heart failure (Eisenmenger’s physiology).

V-73. The answer is D. (Chap. 239) The patient has a classic presentation for acute pericarditis with constant or pleuritic chest pain, exacerbated by lying flat and alleviated by sitting forward. Serum biomarkers may show mild evidence of myocardial injury from myocardial inflammation, but are generally not substantially elevated. Friction rub is frequently present, has three components, and is best heard while the patient is upright and leaning forward. In the acute stages, ECG classically shows ST-segment elevation with upward concavity in two or three standard limb leads and V2 through V6 with reciprocal changes in aVR. Convex curvature is more commonly found in acute myocardial infarction. PR depression may be found. After several days, the ST changes resolve and T waves become inverted. After weeks to months, the ECG returns to normal.

V-74. The answer is B. (Chap. 239) Pulsus paradoxus is an exaggeration of the normal phenomenon in which systolic blood pressure declines 10 mmHg or less with inspiration. Pulsus paradoxus is typically seen in patients with pericardial tamponade and in patients with severe obstructive lung disease (COPD, asthma). In pulsus paradoxus due to pericardial tamponade, the inspiratory systolic blood pressure decline is greater due to the tight incompressible pericardial sac. The right ventricle distends with inspiration, compressing the left ventricle and resulting in decreased systolic pulse pressure in the systemic circulation. In severe obstructive lung disease, the inspiratory decline of systolic blood pressure may be due to the markedly negative pleural pressure either causing left ventricular compression (due to increased RV venous return) or increased LV impedance to ejection (increased afterload).

V-75. The answer is C. (Chap. 239) Beck’s triad can be used to alert clinicians to the potential presence of cardiac tamponade. The principal features are hypotension, muffled or absent heart sounds, and elevated neck veins, often with prominent x-descent and absent y-descent. These are due to the failure of ventricular filling and limited cardiac output. Kussmaul’s sign is seen in restrictive cardiomyopathy and pericardial constriction, not tamponade. Friction rub may be seen in any condition associated with pericardial inflammation.

V-76. The answer is D. (Chap. 239) This patient’s presentation and physical examination are most consistent with the diagnosis of constrictive pericarditis. The most common cause of constrictive pericarditis worldwide is tuberculosis, but given the low incidence of tuberculosis in the United States, constrictive pericarditis is a rare condition in this country. With the increasing ability to cure Hodgkin’s disease with mediastinal irradiation, many cases of constrictive pericarditis in the United States involve patients who received curative radiation therapy 10–20 years prior. These patients are also at risk for premature coronary artery disease. Risks for these complications include dose of radiation and radiation windows that include the heart. Other rare causes of constrictive pericarditis are recurrent acute pericarditis, hemorrhagic pericarditis, prior cardiac surgery, mediastinal irradiation, chronic infection, and neoplastic disease. Physiologically, constrictive pericarditis is characterized by the inability of the ventricles to fill because of the noncompliant pericardium. In early diastole, the ventricles fill rapidly, but filling stops abruptly when the elastic limit of the pericardium is reached. Clinically, patients present with generalized malaise, cachexia, and anasarca. Exertional dyspnea is common, and orthopnea is generally mild. Ascites and hepatomegaly occur because of increased venous pressure. In rare cases, cirrhosis may develop from chronic congestive hepatopathy. The jugular venous pressure is elevated, and the neck veins fail to collapse on inspiration (Kussmaul’s sign). Heart sounds may be muffled. A pericardial knock is frequently heard. This is a third heart sound that occurs 0.09–0.12 seconds after aortic valve closure at the cardiac apex. Right heart catheterization would show the “square root sign” characterized by an abrupt y-descent followed by a gradual rise in ventricular pressure. This finding, however, is not pathognomonic of constrictive pericarditis and can be seen in restrictive cardiomyopathy of any cause. Echocardiogram shows a thickened pericardium, dilatation of the inferior vena cava and hepatic veins, and an abrupt cessation of ventricular filling in early diastole. Pericardial resection is the only definitive treatment of constrictive pericarditis. Diuresis and sodium restriction are useful in managing volume status preoperatively, and paracentesis may be necessary. Operative mortality ranges from 5–10%. Underlying cardiac function is normal; thus, cardiac transplantation is not indicated. Pericardiocentesis is indicated for the diagnostic removal of pericardial fluid and cardiac tamponade, which is not present on the patient’s echocardiogram. Mitral valve stenosis may present similarly with anasarca, congestive hepatic failure, and ascites. However, pulmonary edema and pleural effusions are also common. Examination would be expected to demonstrate a diastolic murmur, and echocardiogram should show a normal pericardium and a thickened immobile mitral valve. Mitral valve replacement would be indicated if mitral stenosis were the cause of the patient’s symptoms.

V-77. The answer is C. (Chap. 240) Blunt, nonpenetrating trauma such as that described here can result in commotio cordis, which occurs when the trauma impacts the heart during the susceptible phase of repolarization just before the peak of the T wave and results in ventricular fibrillation. This syndrome is most common in young athletes who are playing hockey, football, baseball, or lacrosse, for example. Treatment is prompt defibrillation. While aortic rupture, myocardial rupture with cardiac tamponade, and tension pneumothorax may occur with chest wall trauma, their presentation should be less immediate after the trauma. Hypertrophic cardiomyopathy may present with sudden cardiac death, as in this case, but the preceding chest trauma makes commotio cordis more likely.

V-78. The answer is E. (Chap. 247) The patient presents with prehypertension, as evidenced by systolic blood pressure of 120–139 mmHg or diastolic blood pressure of 80–89 mmHg. Although at this blood pressure medication therapy is not indicated, the MRFIT trial clearly showed a graded influence of both systolic and diastolic blood pressure on cardiovascular mortality including down to within normal range at 120 mmHg systolic. Thus, lifestyle modification is in order for the patient described here. Alcohol consumption is recommended to be two or fewer drinks per day for men and one drink or less per day for women. NaCl consumption of less than 6 g per day has been shown to reduce blood pressure in patients with established hypertension and in certain ethnic groups. To reduce blood pressure, regular moderate to intense aerobic activity for 30 minutes 6–7 days per week is recommended. Finally, a weight loss of 9.2 kg has been shown to drop blood pressure on average 6/3 mmHg.

V-79. The answer is C. (Chap. 247) Several factors have been shown to confer an increased risk of complications from hypertension. In the patient described here there is only one: ongoing tobacco use. Epidemiologic factors that have poorer prognosis include African-American race, male sex, and onset of hypertension in youth. In addition, comorbid factors that independently increase the risk of atherosclerosis worsen the prognosis in patients with hypertension. These factors include hypercholesterolemia, obesity, diabetes mellitus, and tobacco use. Physical and laboratory examination showing evidence of end organ damage also may portend a poorer prognosis. This includes evidence of retinal damage or hypertensive heart disease with cardiac enlargement or congestive heart failure. Furthermore, electrocardiographic evidence of ischemia or left ventricular strain but not left ventricular hypertrophy alone may predict worse outcomes. A family history of hypertensive complications does not worsen the prognosis if diastolic blood pressure is maintained at less than 110 mmHg.

V-80 and V-81. The answers are D and E, respectively. (Chap. 247) This patient presents at a young age with hypertension that is difficult to control, raising the question of secondary causes of hypertension. The most likely diagnosis in this patient is primary hyperaldosteronism, also known as Conn’s syndrome. The patient has no physical features that suggest congenital adrenal hyperplasia or Cushing’s syndrome. In addition, there is no glucose intolerance, as is commonly seen in Cushing’s syndrome. The lack of episodic symptoms and the labile hypertension make pheochromocytoma unlikely. The findings of hypokalemia and metabolic alkalosis in the presence of difficult to control hypertension yield the likely diagnosis of Conn’s syndrome. Diagnosis of the disease can be difficult, but the preferred test is the plasma aldosterone/renin ratio. This test should be performed at 8 a.m., and a ratio above 30 to 50 is diagnostic of primary hyperaldosteronism. Caution should be taken in interpreting this test while the patient is on ACE inhibitor therapy, as ACE inhibitors can falsely elevate plasma renin activity. However, a plasma renin level that is undetectable or an elevated aldosterone/renin ratio in the presence of ACE inhibitor therapy is highly suggestive of primary hyperaldosteronism. Selective adrenal vein renin sampling may be performed after the diagnosis to help determine if the process is unilateral or bilateral. Although fibromuscular dysplasia is a common secondary cause of hypertension in young females, the presence of hypokalemia and metabolic alkalosis should suggest Conn’s syndrome. Thus, magnetic resonance imaging of the renal arteries is unnecessary in this case. Measurement of 24-hour urine collection for potassium wasting and aldosterone secretion can be useful in the diagnosis of Conn’s syndrome. The measurement of metanephrines or cortisol is not indicated.

V-82. The answer is B. (Chap. 248) For all patients with aortic dissection or hematoma, appropriate management includes reduction of shear stress with beta blockade and management of systemic hypertension to reduce tension on the dissection. However, emergent or urgent surgical therapy is indicated to patients with ascending aortic dissection and intramural hematomas (type A), and for complicated type B dissections (distal aorta). Complications that would warrant surgical intervention include propagation despite medical therapy, compromise of major branches, impending rupture, or continued pain. Thus, patient B has a distal dissection without evidence of complications and is the best candidate for medical therapy.

V-83. The answer is B. (Chap. 248) Abdominal aortic aneurysms (AAAs) affect 1–2% of men older than age 50. Most AAAs are asymptomatic and are found incidentally on physical examination. The predisposing factors for AAA are the same as those for other cardiovascular disease, with over 90% being associated with atherosclerotic disease. Most AAAs are located infrarenally, and recent data suggest that an uncomplicated infrarenal AAA may be treated with endovascular stenting instead of the usual surgical grafting. Indications for proceeding to surgery include any patient with symptoms or an aneurysm that is growing rapidly. Serial ultrasonography or CT imaging is imperative, and all aneurysms larger than 5.5 cm warrant intervention because of the high mortality associated with repair of ruptured aortic aneurysms. The rupture rate of an AAA is directly related to size, with the 5-year risk of rupture being 1–2% with aneurysms less than 5 cm and 20–40% with aneurysms greater than 5 cm. The mortality of patients undergoing elective repair is 1–2% and is greater than 50% for the emergent treatment of a ruptured AAA. Preoperative cardiac evaluation before elective repair is imperative, as coexisting coronary artery disease is common.

V-84. The answer is E. (Chap. 248) Aortitis and ascending aortic aneurysms are commonly caused by cystic medial necrosis and mesoaortitis that result in damage to the elastic fibers of the aortic wall with thinning and weakening. Many infectious, inflammatory, and inherited conditions have been associated with this finding, including syphilis, tuberculosis, mycotic aneurysm, Takayasu’s arteritis, giant cell arteritis, rheumatoid arthritis, and the spondyloarthropathies (ankylosing spondylitis, psoriatic arthritis, Reiter’s syndrome, Behçet’s disease). In addition, it can be seen with the genetic disorders Marfan’s syndrome and Ehlers-Danlos syndrome.

V-85. The answer is E. (Chap. 248) Descending aortic aneurysms are most commonly associated with atherosclerosis. The average growth rate is approximately 0.1–0.2 cm yearly. The risk of rupture and subsequent management are related to the size of the aneurysm as well as symptoms related to the aneurysm. However, most thoracic aortic aneurysms are asymptomatic. When symptoms do occur, they are frequently related to mechanical complications of the aneurysm causing compression of adjacent structures. This includes the trachea and esophagus, and symptoms can include cough, chest pain, hoarseness, and dysphagia. The risk of rupture is approximately 2–3% yearly for aneurysms less than 4 cm and increases to 7% per year once the size is greater than 6 cm. Management of descending aortic aneurysms includes blood pressure control. Beta blockers are recommended because they decrease the contractility of the heart and thus decrease aortic wall stress, potentially slowing aneurysmal growth. Individuals with thoracic aortic aneurysms should be monitored with chest imaging at least yearly, or more frequently if new symptoms develop. This can include CT angiography, MRI, or transesophageal echocardiography. Operative repair is indicated if the aneurysm expands by more than 1 cm in a year or reaches a diameter of more than 5.5–6.0 cm. Endovascular stenting for the treatment of thoracic aortic aneurysms is a relatively new procedure with limited long-term results available. The largest study to date included more than 400 patients with a variety of indications for thoracic endovascular stents. In 249 patients, the indication for stent was thoracic aortic aneurysm. This study showed an initial success rate of 87.1%, with a 30-day mortality rate of 10%. However, if the procedure was done emergently, the mortality rate at 30 days was 28%. At 1 year, data were available on only 96 of the original 249 patients with degenerative thoracic aneurysms. In these individuals, 80% continued to have satisfactory outcomes with stenting and 14% showed growth of the aneurysm (LJ Leurs, J Vasc Surg 40:670, 2004). Ongoing studies with long-term follow-up are needed before endovascular stenting can be recommended for the treatment of thoracic aortic aneurysms, although in individuals who are not candidates for surgery, stenting should be considered.

V-86. The answer is C. (Chap. 249) The patient presents with classic signs of arterial occlusion with limb pain, physical examination showing pallor, and a pulseless, cold leg. She has no risk factors for central or peripheral atherosclerotic disease; thus angiogram would simply confirm the diagnosis of arterial occlusion, not demonstrate her predisposing condition. In the absence of fever or systemic symptoms, vasculitis and endocarditis are unlikely sources of arterial embolization. She likely had a paradoxical embolism in the context of an atrial septal defect, which was the source of her childhood murmur. Because many of these patients develop pulmonary hypertension with time, she is now at risk for a paradoxical embolism. Although in this context, arterial emboli frequently originate from venous thrombus, the thrombi cannot produce a paradoxical embolism in the absence of right-to-left shunt, such as in a large patent foramen ovale or an atrial septal defect.