Systolic Time Intervals in Right Ventricular Volume Overload: An Echocardiographic Study

The analysis of systolic time intervals (STI) has provided an indirect method of assessing left ventricular performance in man (1–4). These intervals are conveniently derived from the simultaneous recording of the electrocardiogram, the indirect carotid pulse tracing, and the phonocardiogram. Noninvasive measurement of right ventricular STI, however, has not been possible because of the inability to define the onset of right ventricular ejection. Recently echocardiography has been used to determine right as well as left ventricular STI (5–7).