Systolic and diastolic cardiac function time intervals and exercise capacity in women.

Abstract

To determine the relationship between exercise capacity and resting cardiac function time intervals in women. The noninvasive method of seismocardiography was used to measure resting cardiac intervals in 12 female subjects. On the basis of maximal treadmill time (Bruce protocol), two groups were studied and categorized as long duration runners (LDR; N = 6) or short duration runners (SDR, N = 6). The following resting atrial and left ventricular (LV) cardiac function time intervals were determined: atrial systole, LV systole, LV diastole, LV isovolumetric contraction, LV isovolumetric relaxation, LV ejection, LV preejection, LV filling, LV rapid filling, and Tei index. Heart rate (HR) (65+/-3 vs 61+/-4 b x min(-1) for LDR and SDR, respectively; P = NS) and atrial systolic time (75+/-6 vs 81+/-5 ms for LDR and SDR, respectively; P = NS) were similar between groups. LV systole (348+/-15 vs 302+/-8 ms for LDR and SDR, respectively; P < 0.05) and LV ejection (297+/-13 vs 247+/-7 ms for LDR and SDR, respectively; P < 0.01) were longer in LDR, despite a similar LV isovolumetric contraction time. There was a general trend for a shortened LV diastole in LDR with a significantly shortened LV isovolumetric time in LDR (80+/-8 vs 107+/-8 ms for LDR and SDR, respectively; P < 0.05). LV preejection was shorter in LDR versus SDR (LDR; 114+/-6 vs SDR; 130+/-3 ms, P < 0.05), and the Tei index was less in LDR versus SDR. Independent of HR, increased treadmill time in young women is associated with greater resting systolic time intervals and decreased diastolic cardiac function time intervals.