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.
When the heart does not get enough oxygen from the coronary arteries, you feel a squeezing chest pain or pressure across your chest that usually goes away after you stop the activity. The most common cause of angina is hardening of the arteries (atherosclerosis).Chest pain that is fairly predictable and usually occurs when you exercise is called stable angina. It is relieved with rest or nitroglycerin.Chest pain that occurs when you are resting, or at unpredictable times, is known as unstable angina.oronary heart disease, which occurs when the arteries leading to the heart become narrowed or blocked by plaque, is almost always the cause of angina. Environmental situations, such as cold exposure, emotional stress, or heavy metals can induce angina.