What is cardiac cycle ? How does it occur?

Explanation

1) The sequential events in the which are cyclically repeated are called cardiac cycle.
2) The cardiac cycle includes an active phase systole and a resting phase the diastole of atria and ventricles.
3) The contraction phase of the heart beat is called systole and the relaxation phase of heart beat is diastole.
4) The whole process of cardiac cycle is completed in approximately 0.8 seconds.
5) The time needed for atrial contraction is `0.11-0.14` seconds.
6) The time needed for ventricualar contraction is `0.27-0.35` seconds.