Valvular Heart Disease

Question 1

Describe the cause and classic history of Mitral stenosis

Answer 1

Cause: RF is the most common cause

History: Dyspnea, orthopnea, and PND (paroxysmal nocturnal dyspnea)

Question 2

Describe the cause and classic history of Mitral regurgitation

Answer 2

Cause: Typically results from RF or chordae tendinae rupture after MI

History; Fatigue, dyspnea, orthopnea

Question 3

Describe the cause and classic history of Aortic stenosis

Answer 3

Cause: Typically seen in the elderly; bicuspid or unicuspid valves may lead to symptoms in childhood

History: Usually asymptomatic for years and begins with DOE; progresses to angina, syncope, and heart failure, with the mortality rate increasing through this progression

Question 4

Describe the cause and classic history of Aortic regurgitation

Answer 4

Cause: CREAM mnemonic: congenital, rheumatic damage, endocarditis, aortic dissection/aortic root dilation, Marfan syndrome

History: Symptoms in acute cases include severe dyspnea, acute pulmonary congestion, and cardiogenic shock; symptoms in chronic cases include DOE, orthopnea, and PND

Question 5

What physical examination findings are associated with Mitral stenosis

Answer 5

Physical Characteristics: Late diastolic blowing murmur (best heard at the apex)

Other findings: Opening snap, loud S1, AF, LAE, PH

Question 6

What physical examination findings are associated with Mitral regurgitation

Answer 6

Physical characteristics: Holosystolic murmur (radiates to the axilla)

Other Findings: Soft S1, LAE, PH, LVH

Question 7

What physical examination findings are associated with Aortic stenosis

Answer 7

Physical characteristics: Harsh systolic ejection murmurs (best heard in the aortic area; radiates to the carotid arteries)

Other findings: Slow pulse upstroke, S3/S4, ejection click, LVH, cardiomegaly; syncope, angina, heart failure

Question 8

What physical examination findings are associated with Aortic regurgitation

Answer 8

Physical Characteristics: Early diastolic decrescendo murmur (best heard at apex)

Other findings: Widened pulse pressure, LVH, LV dilation, S3 Mitral prolapse Midsystolic click, late systolic murmur Panic disorder

Question 9

Describe the treatment of Mitral stenosis

Answer 9

Mitral stenosis is a mechanical problem and requires balloon valvotomy or surgery if it becomes severe. Medical management (diuretics, digoxin, beta-blockers) is only adjunctive to either percutaneous or surgical intervention.

Question 10

Describe the treatment of Mitral regurgitation

Answer 10

Mitral regurgitation is treated with corrective surgery if certain indications are present (flail leaflet, severe regurgitation). Vasodilators (nitroprusside, hydralazine) may be used in symptomatic patients. Atrial fibrillation is common because of left atrial enlargement and is treated with either cardioversion or rate control and anticoagulation. as appropriate, if it is present. Aortic valve replacement should be performed in essentially all patients with symptomatic

Question 11

Describe the treatment of aortic stenosis.

Answer 11

Aortic valve replacement or repair is indicated in symptomatic patients with chronic

Question 12

Describe the treatment of ortic regurgitation.

Answer 12

Aortic valve replacement or repair may be indicated for asymptomatic patients under certain circumstances, such as progressive left ventricular enlargement (along with specific echocardiographic findings that are beyond the scope of the USMLE). Vasodilators may be used to reduce the hemodynamic burden and possibly delay the need for surgery in asymptomatic patients.

Question 13

True or false: An understanding of the pathophysiology behind the various changes associated with longstanding valvular heart disease is of high yield for the Step 3 exam.

Answer 13

True. For example, it is advisable to understand why right ventricular failure may occur with longstanding mitral stenosis. This is not memorization but rather an ability to determine rationally which changes are associated with each type of valvular dysfunction.

Question 14

What are the recommendations for endocarditis prophylaxis?

Answer 14

The 2008 American Heart Association recommendations conclude that only an extremely small number of cases of infective endocarditis might be prevented by antibiotic prophylaxis for dental procedures. Cardiac conditions for which prophylaxis for dental procedures is recommended include a prosthetic cardiac valve, previous infectious endocarditis, congenital heart disease, and a cardiac transplant in recipients who develop valvulopathy. Antibiotic prophylaxis is no longer recommended for genitourinary or gastrointestinal procedures. If a prophylactic antibiotic is indicated, it should be administered in a single dose before the procedure. Amoxicillin is the preferred choice for oral therapy. Cephalexin, clindamycin, azithromycin, or clarithromycin may be used in patients with penicillin allergy. Ampicillin, cefazolin, ceftriaxone, or clindamycin may be used for patients unable to take oral medication.

Question 15

Describe the two clinical types of endocarditis. What are the causative organisms?

Answer 15

1. Acute (fulminant) endocarditis typically affects normal heart valves and

is most commonly caused by S. aureus.

2. Subacute endocarditis has an insidious
   onset and typically affects previously damaged or prosthetic valves.

The most common cause is Streptococcus viridans, but other streptococcal and staphylococcal species may also cause endocarditis (e.g., Staphylococcus epidermis, Streptococcus bovis, and enterococci). Suspect colon cancer if S. bovis is detected in a blood culture.

Question 16

What elements of a medical history point to endocarditis?

Answer 16

Look for patients who are more likely to be affected by endocarditis: • Intravenous drug abusers, who usually have right-sided lesions, although left-sided lesions are much more common in the general population • Patients with abnormal heart valves (e.g., prosthetic valves, rheumatic valvular disease, and congenital heart defects such as tetralogy of Fallot) • Postoperative patients (especially after dental surgery)

Question 17

How is endocarditis diagnosed and treated?

Answer 17

The diagnosis is generally made on the basis of blood cultures. Empiric treatment is started until the culture and sensitivity results are known. An antistaphylococcal penicillin (such as oxacillin or nafcillin, or vancomycin if methicillin-resistant S. aureus is suspected) plus an aminoglycoside is a good choice for native valve endocarditis. A third-generation penicillin or cephalosporin plus an aminoglycoside is a reasonable choice. Empiric treatment for prosthetic valve endocarditis is vancomycin plus gentamicin plus either cefepime or a carbapenem.

Question 18

What are the classic signs and symptoms of endocarditis?

Answer 18

Look for general signs of infection (e.g., fever, tachycardia, malaise) plus a new-onset heart murmur, embolic phenomena (stroke and other infarcts), Osler nodes (painful nodules on the tips of the fingers), Janeway lesions (nontender erythematous lesions on the palms and soles), Roth spots (round retinal hemorrhages with white centers), and septic shock (more likely for acute than subacute disease).

Question 19

What are the major and minor Jones criteria for rheumatic fever? Why is rheumatic fever less common today?

Answer 19

The five major Jones criteria include migratory polyarthritis, carditis, chorea, erythema marginatum, and subcutaneous nodules. The minor Jones criteria include elevations in the erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and antistreptolysin O titer; prolonged PR interval on ECG; and arthralgia. The diagnosis of rheumatic fever requires a history of streptococcal infection and the presence of two of the major criteria, or one major criterion plus two minor criteria. Treatment of streptococcal pharyngitis with antibiotics markedly reduces the incidence of rheumatic fever; thus the condition is less common today. Give all patients affected by rheumatic fever endocarditis prophylaxis before surgical procedures. A way to remember the major Jones criteria is with the mnemonic JONES: joints, obvious (the heart!), nodules, erythema marginatum, Syndenham chorea.