ABSTRACT
With stroke volume preferentially ejected into the LA, forward flow drops, resulting in an accompanying sudden decrease in systemic cardiac output and tissue perfusion.
Clinical presentation SYMPTOMS Symptoms vary with the size of the regurgitant volume. Mild MR (regurgitant volume <20 ml) is usually well tolerated even if it develops suddenly. A limitation in ability to perform strenuous tasks may be all that is noticed. Moderate MR (regurgitant volume 20-40 ml) commonly produces fatigue and dyspnea with normal activities. Atrial fibrillation, precipitated by stretch of the LA, may produce palpitations. At the extreme end of acute MR (volume >60 ml) typified by rupture of a papillary muscle (116), patients often present with the sudden onset of atypical chest pain, cardiogenic shock, and pulmonary edema. In acute MR due to a reversible cause (e.g. ischemic papillary dysfunction), a patient may present with pulmonary edema which clears rapidly with diuresis and antianginal therapy.
