The SAN is found in the top of the right atrium and sets the rate at which the heart contracts. It sends out electrical impulses which are carried through the muscular walls of both atria.

The left and right atrium are the upper chambers, and the left and right ventricles are the bottom chambers. Heart valves open to allow blood to flow between the chambers and in and out of the heart.

Tricuspid regurgitation is a condition that causes a heart valve to leak blood back into the right atrium of the heart. If left untreated, it can cause life threatening complications. Learn more.

Right atrium functions as the entryway to the heart, pushing blood towards right ventricle and the lungs. It also houses the pacemaker of the heart, the sinoatrial node, that initiates and maintains ...

Left ventricular size and function were normal. The right atrium measured 11 × 12 cm and had a calculated volume of 760 (normal 20–40) mL — representing one of the largest right atria described in an ...