MITRAL REGURGITATION   20A

A 58-year-old man presents to the emergency department with 20 minutes of crushing substernal chest pain and marked shortness of breath. Physical examination shows inspiratory crackles over the lower three-quarters of both lung fields, basilar dullness to percussion, hyperdynamic left ventricular (LV) impulse, brisk carotid upstroke, pansystolic murmur at the apex that radiates into the axilla, and S₃ gallop. Electrocardiography (ECG) shows ST-segment elevations in leads II, III, and aVF. Chest radiography shows Kerley B lines and bilateral pleural effusions consistent with acute pulmonary edema. Doppler echocardiography shows severe mitral regurgitation, and transesophageal echocardiography reveals a posterior mitral leaflet prolapsing into the left atrium (LA) and dyskinesis of basal lateral wall segment of the LV. The diagnosis is posterolateral myocardial infarction (MI) with acute mitral regurgitation resulting from papillary muscle ischemia and rupture.

What are the salient features of this patient’s problem? How do you think through his problem?

Salient features: Crushing chest pain and myocardial ischemia; shortness of breath; crackles, dullness to percussion, and S₃ gallop and chest radiography indicating pulmonary edema; hyperdynamic LV, brisk carotid upstroke, and pansystolic murmur at the apex radiating to the axilla; echocardiogram diagnostic of mitral regurgitation

How to think through: This patient presents with an ST-elevation MI and acute left heart failure (HF). What complications of acute MI lead to acute HF? (LV myocardial dysfunction, rupture of the septum or LV free wall with tamponade, arrhythmia, or acute valvular dysfunction.) What examination findings suggest acute mitral regurgitation as the cause of HF? (The character of the murmur, hyperdynamic precordium, and brisk carotid upstroke.) In acute MI, true rupture of the papillary muscles is much less common than papillary muscle dysfunction or displacement (caused by LV dilatation). With dysfunction or displacement, angiography and percutaneous revascularization are often first steps, the mitral regurgitation resolving with reperfusion. Here echocardiography reveals the posterior mitral leaflet prolapsing into the LA, suggesting papillary muscle rupture. What is the optimum intervention? (Emergent coronary artery bypass grafting with mitral valve repair or replacement.)

MITRAL REGURGITATION   20B

What are the essentials of diagnosis and general considerations regarding mitral regurgitation?

Essentials of Diagnosis

Pansystolic murmur at the apex, radiating into the axilla; associated with S₃ when regurgitant volume is great

ECG with LA abnormality, left ventricular hypertrophy (LVH), and often atrial fibrillation; LA and LV enlargement on radiograph

Echocardiographic findings are diagnostic and can help decide when to operate

General Considerations

The cause and acuity of mitral regurgitation determines the clinical presentation; it may be asymptomatic or cause left-sided HF

Mitral regurgitation results from

    Ischemia at base or rupture of papillary muscle (myocardial ischemia or infarction or infection [endocarditis])

    Displacement of papillary muscles (dilated cardiomyopathy)

    Excessive length of chordae or myxomatous degeneration of leaflets (mitral valve prolapse)

    Noncontraction of annulus (annular calcification)

    Scarring (rheumatic fever, calcific invasion)

Stay updated, free articles. Join our Telegram channel

Join