The cardiac ventricles, of which there are 2 in humans, are the lower chambers of the heart. The left ventricle, larger than the right and with a thicker wall, has an oval shape, it receives oxygenated blood through the atrium and, by contraction, propels it into the body through the aorta. The right ventricle, triangular in shape, receives venous blood through the right atrium and propels it to the lungs through the pulmonary artery. The ventricles have 2 valves: one that separates the ventricle from the corresponding atrium (mitral and tricuspid valves) and one that separates the ventricle from the corresponding artery (aortic and pulmonary valve). When the pump function of a ventricle is impaired, it is referred to as right ventricular failure, left ventricular failure, or congestive heart failure, as appropriate. Right ventricular failure may result from pulmonary embolism, pulmonary hypertension, or chronic respiratory failure. Left ventricular failure may result from myocardial infarction, mitral valve disease, hypertension or cardiomyopathy.