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.
Supraventricular Tachycardia (SVT) An arrhythmia is an abnormality in the timing or pattern of the heartbeat. Arrhythmias may cause the heart to beat too rapidly, too slowly, or irregularly. They are common and may cause a wide variety of symptoms, such as a racing, skipping or fluttering sensation (called palpitations) in your chest.