Midsystolic Clicks in Arteriosclerotic Heart Disease

Abstract

Midsystolic clicks (MSC), or nonejection systolic clicks, were discovered in 15 patients with arteriosclerotic heart disease (ASHD). The diagnosis of ASHD was established by the presence of angina or the history of a documented myocardial infarction (MI) or both. The MSCs were recorded in 13 patients. A late systolic murmur was introduced by the MSC in four patients, and one patient had a soft holosystolic murmur. The mitral origin of the MSCs and murmurs was established by noting their change in timing and intensity following administration of vasoactive drugs. One patient underwent cardiac catheterization, and evidence of an old MI and papillary muscle dysfunction (PMD) was demonstrated. We think that the PMD that occurs secondary to ischemic fibrosis in ASHD permits slack chordae tendineae suddenly to become taut in midsystole and produce a snap. Although the mechanism for the production of chordal snaps has been previously postulated, ASHD has only recently been found responsible for producing these sounds. The diagnosis of ASHD should be considered in patients with MSCs, even though they frequently occur in its absence.