The significance of late systolic murmurs

1. 1. Four patients with apical systolic murmurs confined to mid-late systole, and 3 patients with pansystolic murmurs with late accentuation were subjected to left ventricular cineangiocardiography. Regurgitation of dye into the left atrium during ventricular systole occurred in all 7 patients. 2. 2. Inhalation of amyl nitrite, a Valsalva maneuver, and intravenous injection of phenylephrine resulted in a fairly constant alteration in the intensity and the time of maximal accentuation of these murmurs. The conclusion is that the pattern of change is compatible with that of a mitral regurgitant systolic murmur. 3. 3. The common association of late murmurs with mid-late systolic clicks is confirmed, and reasons for suspecting that these clicks are due to fibrosed chordae are discussed. 4. 4. The importance of appreciating that late systolic murmurs are due to mildmitral incompetence is stressed. Although little hemodynamic alteration is present, these patients are presumably potential candidates for subacute bacterial endocarditis, and, in younger patients, prophylaxis against rheumatic activity is indicated. © 1963.