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.
1 If the blood clot is large enough, it can block blood from exiting the right side of the heart, thus preventing blood from entering the lungs.  No blood enters the left side of the heart to pump blood throughout the rest of the body. This can result in shock (circulatory collapse) and sudden death.