The effects of age, activity status, and blood pressure on systolic time intervals (STI), including electromechanical systole (QS2), left ventricular ejection time (LVET), pre ejection period (PEP), and their heart rate corrected indices, QS21, LEVTI, and PEPI, were analyzed in 315 male subjects aged 20-89 yr. An elevated diastolic blood pressure (≥ 90 mm Hg) was significantly correlated with prolongation of the PEP, PEPI and QS21. An elevated systolic blood pressure (≥ 140 mm Hg) was significantly correlated with prolongation of the LVET, LVETI, QS2, and QS21. Neither coronary heart disease, functional Class 1 (67 subjects), nor estimated daily physical activity (range 1623-5752 cal/24 hr) were significantly related to STI. In 218 healthy normotensive subjects, a significant but small prolongation of the PEP and PEPI (4 msec/decade) and QS21 (5 msec/decade) was found from the 3rd through the 6th decade with a decline in these intervals in the 7th and 8th decades.
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