ERA. 1  baseball, baseball game - a ball game played with a bat and ball between two teams of nine players; teams take turns at bat trying to score runs; he played baseball in high school; there was a baseball game on every empty lot; there was a desire for National League ball in the area; play ball!.
The contraction of the heart muscle starts in the two atria, which push the blood into the ventricles. Then the walls of the ventricles squeeze together and force the blood out into the arteries: the aorta to the body and the pulmonary artery to the lungs.
This is important because when you have AFib, the irregular heartbeat can allow blood to be trapped in the upper chambers of the heart, which can cause blood clots to form. And if a clot leaves the heart, it can travel to the brain and cause a stroke. Learn how AFib can cause blood clots that may lead to stroke.