The Syndrome of Apical Systolic Click, Late Systolic Murmur, and Abnormal T Waves

DEVELOPMENT of new diagnostic techniques often brings to our attention conditions previously described but rarely recognized and little understood. So it is with this syndrome, reported in bits about once every generation from 1887 till the past decade. Then the pieces began to fall into place, and now several articles are appearing every year, each with more information and larger numbers of subjects. The syndrome is characterized by distinctive auscultatory and electrocardiographic features. Typically in a healthy and asymptomatic young woman one hears at the apex a click near midsystole, followed by a late systolic murmur. The heart and lungs on roentgenograms appear normal; so it is a surprise to find inverted T waves in the left precordial leads, aVF, and leads II and III. What does it all mean? The diagnostic tests which combined to shed light on these findings were selective angiocardiography and phonocardiography, both extracardiac and intracardiac, with use of pharmacological agents, such as amyl nitrite and phenylephrine, and the Valsalva maneuver. The intracardiac phonocatheter localized the click and murmur to the left atrium and region of the mitral valve.1 The pharmacological and physiological maneuvers showed that the murmur behaves as does a murmur of mitral regurgitation.2 3 Selective