What part of the heart contracts first in the cardiac cycle?

1 Answer
Mar 17, 2016

The atriums contract first.

Explanation:

Blood is pumped from the right atrium down into the right ventricle and from the left atrium down into the left ventricle. In the second stage, the lower chambers contract to push this blood out of the heart to either the body via your main artery (aorta) or to the lungs to pick up oxygen.

Take note that blood flows concurrently at both sides of the heart.