Two-dimensional echocardiographic assessment of papillary muscle contractility in patients with prior myocardial infarction

Abstract

Objectives. This study was performed to assess the length and contractile performance of human left ventricular papillary muscles and to determine the relation between papillary muscle dysfunction and mitral regurgitation.Background. Assessment of human papillary muscle contractility remains a clinical challenge.Methods. Two-dimensional echocardiographic examinations were performed in 16 normal subjects and 31 patients with prior myocardial infarction. Apical echocardiograms were used to obtain long-axis views of the anterior and posterior papillary muscles. The end-systolic and end-diastolic lengths of the papillary muscles were measured and fractional shortening was calculated.Results. Fractional shortening in normal subjects was 27 ± 8% for the anterior papillary muscle and 30 ± 8% for the posterior papillary muscle. In patients with prior myocardial infarction, a significant decrease in fractional shortening was observed in proportion to the severity of left ventricular wall motion abnormalities at the site of papillary muscle implantation. Moderate or severe mitral regurgitation was significantly more frequent in patients with combined anterior and posterior papillary muscle dysfunction than in those with isolated anterior or posterior dysfunction or with normal function of both papillary muscles (p < 0.05).Conclusions. Two-dimensional echocardiography is useful for demonstrating abnormal contractility of human left ventricular papillary muscles. Papillary muscle contractility should be analyzed in each case to elucidate the mechanism of mitral regurgitation in patients with papillary muscle dysfunction.