Systolic Time Intervals in the Syndrome of Midsystolic Click and Late Systolic Murmur

¹ From the Cardiology Division, Department of Medicine, New York Medical College, Flower and Fifth Avenue Hospitals, New York, New York

Left ventricular function, as measured by systolic time intervals, was studied in 30 subjects with the syndrome of midsystolic click and late systolic murmur (ages, 20 to 53 years; mean, 34 ± 9 years). Twenty-one were asymptomatic, six had chest pain, two had palpitations, one had shortness of breath, and one had hypotensive episodes. Each patient had the typical auscultatory and echocardiographic findings of the syndrome of midsystolic click and late systolic murmur. In the study the values for the interval between the onset of the QRS complex (Q) and the aortic component of the second heart sound (A₂) (377 ± 42 msec), the Q-A₂ index (532 ± 39 msec), the preejection period (PEP) (97 ± 17 msec), the PEP index (127 ± 16 msec), the left ventricular ejection time index (403 ± 26 msec) and the ratio of PEP to left ventricular ejection time (0.35 ± 0.01) were not significantly different from the values in 17 controls matched for age. Our study, then, supports the contention that left ventricular function remains well preserved in most patients with the syndrome of midsystolic click and late systolic murmur.