Question

explain how a disruption in any one aspect of the cardiac cycle could effect other aspects of the cycle and/or the proper functioning of the heart itself. What would the consequences be?

Answer 1

Cardiac cycle is a set of event which occurs in heart.

entire cardiac cycle occurs in 0.8 sec and so there are 72 cycles in 1 min which is correlated with heart rate.

cardiac cycle has following events

Cardiac cycle has following events

1- Atrial systole - 0.1 sec - blood moves from atria to ventricle through Atrioventricular valve

2- Ventricular systole - 0.3 sec - it is subdivided into following

A - Isovolumetric contraction - both Atrioventricular valve and aortic and pulmonary valve are closed

B - Rapid ejection - Atrioventricular valve closed but aortic and pulmonary valve are open

3 - Ventricular diastole - 0.5sec - it is also subdivided into

A - Isovolumetric relaxation - Atrioventricular and aortic and pulmonary valve closed

B - Rapid filling - Atrioventricular valve opens and aotic and pulmonary valve are closed

C - slow filling - same as rapid filling but blood flows slowly

4- Atrial diastole - 0.8 sec - Actually atrial diastole start immediately after atrial systole and colides with ventricular systole and there is joint diastole with ventricle

So any change in one event will delay the subsequent event and will show as some clinical signs.

for example, suppose patient has ventricular dysfunction which is characterised by low ventricular function, i.e. ventricle fails to contract as much as it should, so ventricular systole time is reduced which result in low cardiac output which is seen as low ejection fraction on cardiac echo imaging, so in this entire cycle ventricular systole time is reduced and other time like ventricular relaxation is reduced.