Abstract: To investigate the effects of age, sex and heart rate alterations on systolic and diastolic timing intervals, M-mode and Doppler echocardiography were performed in 160 healthy volunteers aged 21 to 97 years,and 36 of them were paced from the right atrium steady to 90, 120 and 160 bearts per minute(BPM). It was found that age-related hemodynamic changes during diastole are characterized by a prolongation of isovolumetric relaxation time(IVRT),A₂E interval and atrial filling period(AFP)(r=0.946, 0.835 and 0.875, P all <0.01), decreased slow filling period(SFP)and the lesser proportion of diastolic filling period(DFP)in the cycle length(r=-0.703 and -0.812, P<0.05 and 0.01). It was also found that with increased heart rate, pre-ejection period(PEP), left ventricular ejection time(LVET)and A2E interval became an increasingly greater proportion of cycle length(r=0.970,0.963 and 0.874, P all <0.01), while DFP occupied a lesser proportion of the cycle length(r=-0.849, P<0.01); Rapid filling period(RFP)and AFP occupied a greater proportion and SFP occupied a lesser proportion of the DEP.With further increase in heart rate,merging of the RFP and AFP occurs. There were no significant differences between men and women in systolic or diastolic timing intervals.These findings suggested that age and heart rate-related physiologic changes should be taken into consideration when evaluating systolic and diastolic timing intervals.

Key words: age, heart rate, echocardiography, Doppler, cardiac cycle