The syndrome of mitral insufficiency due to isolated rupture of the chordae tendineae

Abstract

Clinico-anatomic correlation of the findings in twenty-three cases of ruptured chordae tendineae indicated that rupture associated with other disease of the mitral valve apparatus (group I) differs greatly from isolated rupture of chordae tendineae (group IIA), which presents a distinct clinical-pathologic syndrome. In six additional cases a clinical diagnosis of this syndrome was made (group IIB). Group I represents the end result of a variety of conditions: rheumatic fever, bacterial endocarditis, congenital mitral valve disease and postinfarctional papillary muscle dysfunction. In group IIA no major abnormality of the heart was found and no clinical or pathologic clues to suggest an etiologic factor for rupture of the chordae were detected. The characteristic clinical picture of this syndrome is the result of (1) preferential involvement of the chordae supporting the posterior leaflet of the mitral valve, and (2) the sudden development of mitral valve incompetence. Loss of chordal support by a portion of the posterior leaflet during systole produces a hood-like prolapse of the unsupported portion into the left atrium causing a high velocity jet to be directed toward the upper part of the atrial septum adjacent to the aortic root. This jet creates vibrations heard as a systolic murmur and often felt as a systolic thrill in the “aortic” area of the right upper thorax—a finding closely imitating aortic stenosis. This is the most specific clinical feature of the syndrome of isolated rupture of the chordae tendineae. The sudden appearance of mitral valve incompetence often leads to abrupt development of cardiac failure without the production of gross cardiomegaly, severe left atrial enlargement or atrial fibrillation. This sudden development is not specific for isolated rupture but occurs in other forms of mitral insufficiency, notably after bacterial endocarditis. Clinical identification of this syndrome has practical significance because of the availability of low-risk corrective valvuloplasty, which has been shown to produce satisfactory and lasting results. Analysis of twenty cases of isolated rupture of the chordae tendineae reveals that contrary to common belief, rupture of chordae tendineae is not necessarily a serious cardiac event, as milder forms (presumably due to rupture of a single chorda) are consistent with a fully compensated, asymptomatic state for many years, perhaps even permanently.