Significance of systolic time intervals in predicting prognosis of primary pulmonary hypertension.

To elucidate the characteristics of left ventricular (LV) function and LV shape in primary pulmonary hypertension (PPH), systolic time intervals (STIs) and two-dimensional echocardiograms in seven patients with PPH were studied and compared with those of 12 normal controls. Serial changes in STIs were also analyzed as to clinical outcomes. All patients were females and aged from 14 to 53 years. The follow-up period was 50 +/- 30 months, and five patients died of cardiac causes during the study period. The patients with PPH had a significantly prolonged pre-ejection period (PEP) and PEP index. Left ventricular ejection time (LVET) and the LVET index in the PPH group, at the time of diagnosis, showed no statistical differences compared with those of the controls, but three patients with PPH showed a marked shortening of LVET. A significant decrease in the LVET/PEP ratio was observed in patients with PPH. Left ventricular end-diastolic dimension (EDD) and end-systolic dimension (ESD) were significantly less in patients with PPH than in the controls. No difference in percent fractional shortening of the left ventricle and the mean velocity of circumferential fiber shortening was observed. The degree of LVET shortening correlated with the decrease in EDD (r = 0.97). During follow-up, marked shortening of the LVET index, below approximately 350 msec, was observed immediately before death or clinical deterioration. From these results, we conclude that in PPH, (1) left ventricular function is impaired due to reduced volume of the left ventricle during diastole, reflecting a shortening of LVET and the LVET index, and (2) analysis of serial LVET indexes is useful for predicting the prognosis.