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 Pressure inside your arteries can cause the muscles that line the walls of the arteries to thicken, thus narrowing the passage. 2  A heart attack or stroke can occur if a blood clot blocks blood flow to your heart or brain. 3  Enlarged heart. 4  High blood pressure increases the amount of work for your heart. Enlarged heart. 2  High blood pressure increases the amount of work for your heart. 3  Like any heavily exercised muscle in your body, your heart grows bigger (enlarges) to handle the extra workload. 4  The bigger your heart is, the more it demands oxygen-rich blood but the less able it is to maintain proper blood flow.