What is the cardiac cycle duration (sec) in a man at hea rate of 75/min?
Duration of cardiac cycle (at hea rate of 75/min) is 0.8sec out of which duration of systole is 0.27sec and diastole is 0.53sec. Length of Systole and Diastole: Cardiac muscle has the unique propey of contracting and repolarizing faster when the hea rate is high, and the duration of systole decreases from 0.27 s at a hea rate of 65-0.16 s at a rate of 200 beats/min. The reduced time interval is mainly due to a decrease in the duration of systolic ejection. However, the duration of systole is much more fixed than that of diastole, and when the hea rate is increased, diastole is shoened to a much greater degree. For example, at a hea rate of 65, the duration of diastole is 0.62 s, whereas at a hea rate of 200, it is only 0.14 s Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 30. The Hea as a Pump. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.
0.4
0.8
1
1.6