Rupture of mitral chordae tendineae: Clinical and pathologic observations on seven cases in which there was no bacterial endocarditis

Abstract

The histories and pathologie observations in seven cases of rupture of the mitral chordae tendineae are reviewed. Patients with bacterial endocarditis were excluded from the series. All showed fibrosis and chronic injury of the mitral valve. In two, the lesions were those of rheumatic heart disease; in the remainder, the changes suggested quiescent rheumatic disease, but were not pathognomonic. The chordae of the two valve cusps were ruptured with equal frequency in this series, and usually more than one was broken. The point of rupture lay close to the papillary muscle. The stumps consisted of hyalinized and partially degenerated connective tissue, with a covering of endothelium. Scarring extended into the subjacent myocardium. The corresponding papillary muscles underwent atrophy if all their chordae were broken, but showed hypertrophy if a number were left attached. It was clear from inspection that rupture of the chordae must have allowed a high degree of mitral regurgitation. All hearts were dilated and hypertrophied, with an average weight of 580 grams. The histories of the patients did not indicate that external violence or vigorous exertion were etiologic factors of primary importance in rupture of the mitral chordae tendineae. The symptoms after rupture of the mitral chordae tendineae are those of congestive heart failure, which may be insidious or abrupt in its onset and progressive or remittent in its course. Months or even years may elapse between rupture and the onset of frank congestive failure. Rupture of the chordae is suggested by the sudden appearance of a loud precordial systolic murmur, maximal at the apex and left sternal border, where it is usually accompanied by a thrill. An apical diastolic murmur may also be present. Auricular fibrillation sometimes occurs. Roentgenograms show cardiac enlargement, and fluoroscopic examination may demonstrate systolic pulsation of the left atrium. The differential diagnosis includes bacterial endocarditis, rupture of a valve cusp, rupture of a papillary muscle, and perforation of an infarcted interventricular septum.