Systolic Time Intervals in Isolated Septal Defects before and after Corrective Surgery in Female Patients

Abstract

Systolic time intervals (STI) were evaluated in 19 female patients with uncomplicated ostium secundum atrial septal defect (ASD), before, shortly after (within 2 months) and a long time after the corrective surgery (mean 13.2 years). The measurements were obtained from simultaneous high speed photographic recordings of electrocardiogram, external carotid pulse and phonocardiogram. Before the operation, a significant prolongation of Q-I heart sound interval was detected, together with a less prominent but statistically significant shortening of the left ventricular ejection time; the above alterations were not correlated with the magnitude of the shunt and disappeared shortly after corrective surgery. The STI were still normal a long time after surgical closure of ASD. In accordance with hemodynamic studies reported by other authors, our results confirm that the deviations of STI observed in ASD are due to a reduced diastolic filling of the left ventricle secondary to an apparent decreased distensibility.