Cardiology

Acute mitral regurgitation occurs as a complication of myocardial infarction in perhaps 1% of cases. The characteristic clinical findings include a new systolic murmur occurring in the setting of sudden development of acute congestive heart failure, hypotension, and shock. S3 and S4 gallops and sinus rhythm usually are present, and gross left ventricular or left atrial enlargement usually is not evident radiologically. The immediate and long-term prognoses for patients with acute severe mitral regurgitation are poor without treatment. Although medical therapy can reverse temporarily some of the hemodynamic aberrations, it does not influence survival or eliminate the need for surgical treatment. Surgery consisting of mitral valve replacement and possibly simultaneous coronary revascularization appears to offer some hope in increasing the survival rate among these patients. When acute severe mitral regurgitation is secondary to rupture of chordae tendineae in circumstances other than coronary artery disease, the outlook is not as grim. These patients may show signs and symptoms of congestive heart failure for a few weeks or, at times, many months. Again, sinus rhythm usually is present, with slight left ventircular enlargement, a relatively normal left atrial size, and markedly elevated left atrial and pulmonary arterial pressures. This constellation of findings is indicative of a large mitral regurgitant flow with preservation of left ventricular function and suggests that the patient is likely to benefit greatly from surgical treatment. The prognosis for such patients is much better than it is for the patients with acute mitral regurgitation secondary to coronary artery disease.