Preparing for the American Board of Internal Medicine Maintenance of Certification

Cardiology Review® Online, April 2006, Volume 23, Issue 4

With the next Cardiovascular Disease Exam scheduled for May 10, 2006 (Interventional Cardiology is slated for November 9, 2006) and self-evaluation ongoing, it’s never too early to begin preparing. The following cases and questions should assist in fostering the continuing scholarship required for professional excellence in the practice of medicine. This section will be appearing every other month; we hope you find it useful.

Questions

1. A 52-year-old man has a 1/6 midsystolic heart murmur at the left sternal border and paradoxical splitting of the second heart sound (S2). ________ is the most likely cause of the abnormal S2.

a) Left bundle branch block

b) Right bundle branch block

c) Pulmonary embolism

d) Mitral valve prolapse

e) Atrial septal defect

2. A 62-year-old woman who has had moderately controlled type 2 diabetes mellitus for 15 years is complaining of angina at rest. She is scheduled for coronary arteriography, and considering how diabetes affects her treatment options, which one of the following statements is true?

a) If this woman has more than 50% stenosis of her left main coronary artery, coronary artery bypass graft (CABG) is the best choice.

b) Percutaneous coronary intervention (PCI) is not the best choice in single-vessel disease.

c) With 2-vessel disease and more than 70% proximal left axis deviation lesion, PCI is preferred.

d) If she has congestive heart failure with an ejection fraction below 35%, CABG is clearly the best treatment choice.

3. A 75-year-old woman has long-standing hypertension well controlled with a combination thiazide diuretic and b-blocker. Although she is asymptomatic, her blood pressure has risen significantly to consistent levels of 220/100 mm Hg during the last 6 months, despite careful adherence to her regimen. What is the most likely explanation?

a) Cushing’s syndrome

b) pheochromocytoma

c) obstructive uropathy

d) renovascular hypertension

e) hyperthyroidism

4. Which one of the following statements concerning vitamin E supplementation for heart disease is true? a) There is no difference in all-cause mortality rates with low doses (below 400 IU/d).

b) Higher doses (above 400 IU/d) are associated with lower mortality rates.

c) Effects are more positive with preexisting heart disease.

d) Vitamin E produces no harmful effects.

5. Which one of the following statements about atrial fibrillation (AF) is true? a) The risk of stroke is greater in patients with persistent AF compared with those who have intermittent (paroxysmal) disease.

b) Most episodes of AF are associated with chest pain, palpitations, or heart failure.

c) The overall risk of stroke from AF is greater in a 50-year-old than in a 70-year-old.

d) Aspirin may be a suitable alternative to long-term anticoagulation with warfarin (Cou­madin) for a patient with true lone AF.

e) At least one attempt at rhythm control (conversion of AF to sinus rhythm) should be made in patients with newly detected AF.

6. A 60-year-old woman with elevated blood pressure comes to the office, and you decide to start medication for her hypertension. One week after she begins pharmacologic therapy, routine laboratory evaluation shows that her potassium level is 6.3 mmol/L. Which one of the following antihypertensive drugs would cause this potassium level? a) hydrochlorothiazide (Esidrix, HydroDiuril, Oretic, etc.)

b) spironolactone (Aldactone)

c) enalapril maleate (Vasotec)

d) metoprolol (Lopressor)

e) amlodipine (Norvasc, Amvaz)

7. The most reasonable therapeutic approach for an asymptomatic elderly patient with chronic non-valvular atrial fibrillation is _______________. a) control of the ventricular response and anticoagulation with warfarin (Coumadin) to maintain the international normalized ratio (INR) between 2.0-3.0

b) an attempt at electrical cardioversion and then a repeat of this procedure when needed to maintain normal sinus rhythm

c) electrical cardioversion of the patient initially, followed by use of amiodarone (Cordarone, Pacerone) to maintain normal sinus rhythm

d) control of the ventricular response, but not anticoagulation because of the increased risk of bleeding in the elderly

e) use of either sotalol (Betapace) or amiodarone to convert the rhythm, with anticoagulation to maintain the INR between 1.5-2.5

8. A 73-year-old man comes to the office complaining of lightheadedness and dizziness when standing. You have treated him for many years for hypertension and today note that his blood pressure is well-controlled at 130/82 mm Hg on 2 agents. Which one of the following medications is most likely to cause postural hypotension? a) doxazosin (Cardura)

b) metoprolol (Lopressor)

c) enalapril maleate (Vasotec)

d) carvedilol (Coreg)

9. Which combination of electrocardiographic findings is most suggestive of pulmonary disease with right ventricular hypertrophy or pulmonary hypertension? a) sinus tachycardia, deep S waves in leads V1, and V2, and J-point ST-segment elevation in several lead areas

b) atrial fibrillation, a mean QRS axis of +75°, and inferolateral ST-segment depression

c) right axis deviation, right atrial enlargement, persistent precordial S waves, and ST-segment depression in the inferior and anterior precordial leads

d) indeterminate axis, early transition, and diffuse ST-segment depression

e) normal mean QRS axis, left atrial enlargement, and ST-segment depression in the lateral leads

10. ________________ is the most important treatment objective for heart failure caused by diastolic dysfunction.a) Control of hypertension

b) Adequate diuresis

c) Weight loss

d) Maintaining low-density lipoprotein cholesterol below 100 mg/dL

e) Increasing contractility with positive inotropic agents such as digoxin

Answers

1: a During inspiration, the second heart sound (S2) normally splits into aortic (A2) and pulmonic (P2) components due to the augmented venous return to the right ventricle, thus delaying closure of the pulmonic valve. A delay in aortic valve closure, which causes P2 to precede A2, will result in reversed or paradoxical splitting of S2. Left bundle branch block is the most common cause of delayed closure of the aortic valve.

Atrial septal defect, pulmonary em­bolism, and right bundle branch block may result in splitting S2 that persists during expiration. Mitral valve prolapse, however, does not affect splitting of S2.

Kasper D, Fauci AS, Braunwald E, et al, eds. Harrison’s Principles of Internal Medicine. 16th ed. New York, NY: McGraw-Hill; 2005:1307-1308.

2: a For years, clinicians have understood that diabetic patients with coronary artery disease have different outcomes. Studies have begun to address this issue, and some guidelines are emerging. In significant left-main disease and high-grade proximal left axis deviation, coronary artery by­pass graft (CABG) surgery is the choice just as in nondiabetic patients. For single-vessel disease, the 2 options are almost compatible. Some authors now find percutaneous coronary intervention (PCI) preferred in this situation largely because of the trend toward PCI superiority in drug-eluting stents. For high-risk situations, in­cluding congestive heart failure, myocardial infarction within the last 7 days, and age older than 70 years, many authorities have recommended CABG over PCI. The most recent research maintains that neither is clearly superior, suggesting that a choice should be made based on individual circumstances.

Flaherty JD, Davidson CJ. Diabetes and coronary revascularization. JAMA. 2005;293:1501-1508.

3: d Clues to renovascular disease include the following: ­1) onset of hypertension before the age of 30 (especially without a family history of the disease) or recent onset of significant hypertension after the age of 55; 2) an abdominal bruit, particularly if a diastolic component is present; 3) accelerated or resistant hypertension; 4) recurrent flash pulmonary edema; 5) renal failure of uncertain etiology, especially with a normal urinary sediment; 6) coexisting diffuse atherosclerotic vascular disease, especially in heavy smokers; or 7) acute renal failure precipitated by therapy with an angio­tensin-converting-enzyme inhibitor or angiotensin receptor blocker (under conditions of occult bilateral renal artery stenosis or moderate-to-severe volume depletion).

Noninvasive screening tests include a captopril (Capoten)-enhanced radionuclide renal scan, duplex Doppler flow studies, and magnetic resonance angiography. Renal angiography re­mains the gold standard for identifying renovascular disease, but it carries the risk of radiocontrast-induced acute renal failure or atheroembolism.

Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: The JNC 7 Report. JAMA. 2003;289:2560-2572.

4: a Lower doses of vitamin E have no positive effect on mortality rates in patients with or without preexisting heart disease. Higher doses are associated with a small but significant increase in all-cause mortality, and should therefore be avoided. More research is needed to determine at what point risk increases.

Miller ER III, Pastor-Barriuso R, Dalal D, et al. Meta-analysis: High dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med. 2005;142:37-46.

5: d Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the United States, with an ever-increasing pre­valence due to the aging of our population. Man­age­ment decisions in AF have evolved, especially since publication of the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial. This study confirms that adequate anticoagulation with rate control is a perfectly acceptable option to rhythm control for patients with this disorder.

Patients treated with rhythm control as the therapeutic objective show a trend toward increased morbidity from the adverse effects of long-term antiarrhythmic drug use. With time, the efficacy of these drugs for maintaining sinus rhythm decreases, and recurrence of AF is common, which proves that an attempt at conversion to sinus rhythm for all patients with new-onset AF is not necessary.

More than 90% of patients with AF are asymptomic (unaware they are in AF). The risk of stroke from AF in­creases dramatically with in­creasing age. Stroke risk from intermittent AF is at least equal to that from persistent AF. Patients with true lone AF (those younger than 65 with AF but no un­derlying heart disease) have a relatively low risk for stroke and can therefore be treated with aspirin as an alternative to warfarin.

Wyse DG, Waldo AL, DiMarco JP, et al; Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) Investigators. A com­parison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002;347:1825-1833.

6: b Spironolactone is a specific pharmacologic antagonist of aldosterone, acting primarily through competitive binding of receptors at the aldosterone-dependent, sodium-potassium exchange site in the distal convoluted renal tubule. Spironolactone, a “potassium-sparing” diuretic, causes increased amounts of sodium and water to be excreted and minimizes potassium loss. In fact, its use is limited in some patients because of hyperkalemia.

Liew D, Krum H. Aldosterone receptor antagonists for hypertension: What do they offer? Drugs. 2003;63:1963-1972

7: a The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial showed that achieving adequate anticoagulation (to maintain the international normalized ratio [INR] between 2.0-3.0) and rate control for patients with nonvalvular atrial fibrillation was at least as effective as treatment consisting of medical or electrical attempts at cardioversion with the goal of maintaining sinus rhythm. This approach was also effective in stroke prevention and resulted in fewer hospitalizations and fewer adverse effects. The first episode of atrial fibrillation should perhaps be viewed differently, since medical or electrical cardioversion will most likely be effective in this setting (especially if a precipitating cause can be identified). But when the onset of atrial fibrillation is unknown and longstanding—and the rhythm is fairly well tolerated without producing significant symptoms—a very reasonable approach may be rate control with adequate anticoagulation without an active effort to convert the rhythm and maintain normal sinus rhythm.

Wyse DG, Waldo AL, DiMarco JP, et al; Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Investigators. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002;347:1825-1833.

8: a Postural hypotension is defined as a decrease in standing systolic blood pressure of more than 10 mm Hg, when associated with dizziness or fainting. It is more frequent in older patients with systolic hypertension, diabetes, and those taking agents that can cause volume depletion such as diuretics, venodilators such as nitrates, or a-blockers such as doxazosin.

Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: The JNC 7 report. JAMA. 2003;289:2560-2572.

9: c The electrocardiographic (ECG) di­agnosis of right ventricular hypertrophy (RVH) can best be viewed as a “detective” diagnosis because no single finding is diagnostic. A combination of several findings in conjunction with the right clinical setting (such as long-standing asthma or chronic obstructive pulmonary disease) suggests pulmonary disease on ECG with probable RVH or pulmonary hypertension. At least several of the following ECG findings should be present to suggest the diagnosis: 1) right axis deviation; 2) right atrial enlargement, indicated by a tall, peaked “uncomfortable-to-sit-on” P wave in lead II; 3) incomplete right bundle branch block (or rSR’ pattern in lead V1); 4) low voltage; 5) persistent precordial S waves; 6) “strain” in right ventricular leads (inferior or anterior precordial leads); and 7) tall R wave in lead V1.

Grauer K. 12-Lead ECGs: A Pocket Brain for Easy Interpretation. 3rd ed. Gainesville, Fla: KG/EKG Press; 2005:38-39.

10: a General consensus on the optimal management of patients with heart failure from diastolic dysfunction is lacking because randomized, prospective, controlled clinical trials on the treatment of this disorder do not exist. The one area of agreement on therapeutic approaches is the need for vigorous blood pressure control.

Hyper­tension is by far the most important predisposing factor to development of diastolic dysfunction heart failure, since it leads to concentric hypertrophy with consequently im­paired ventricular compliance and reduced left ventricular filling. The hope is that normalization of blood pressure may reverse some of the abnormalities seen with diastolic dysfunction.

Excessive diuresis may be deleterious in patients with pure diastolic dysfunction (if it leads to volume depletion with further reduction in cardiac output). Increasing contractility with positive inotropic agents is also not indicated. Weight loss and treatment of hyperlipidemia are beneficial lifestyle changes, but not specific for treatment of heart failure with diastolic dysfunction.

Lee TH. Guidelines: Management of heart failure. In: Zipes DP, Libby P, Bonow RO, at al, eds. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia, Pa: WB Saunders; 2004:617-624.