The duration of systolic time interval(STI)in 106 cases was measured from simultaneous recordings of the electrocardiogram(ECG)and phonocardiogram(PCG).The results were compared with the data obtained from simultanaeous photographic recordings of the ECG,PCG,carotid pulse wave(CPW),and apex cardiogram(ACG).There were no significant differences between the two groups(LVETI 421.1l5土16.531 ms versus 419.746±14.286 ms.PEPI 126.471±13.185 ms versus 127.841±12.906 ms,P>0.05).However the former method is simpler.and accurate as well.It seems to be a better method of measuring STI