Cardiac physiology ventricles, pushing open the tricuspid and mitral valves. As pressure drops within the ventricles, blood flows from the major veins into the relaxed atria and from there into the ventricles. Both chambers are in diastole, the atrioventricular valves are open, and the semilunar valves remain closed. The cardiac cycle is complete. One of the simplest methods of assessing the heart's condition is to listen to it using a stethoscope. In a healthy heart, there are only two audible heart sounds, called S1 and S2. The first heart sound S1, is the sound created by the closing of the atrioventricular valves
Short QT syndrome activation lose their pumping ability - fibrillation of the cardiac atria in atrial fibrillation leads to an irregular pulse, and fibrillation of the cardiac ventricles in ventricular fibrillation renders the heart unable to pump blood at all. There are several possible mechanisms by which short action potentials might promote fibrillation. The link between these mechanisms is how the duration of the action potential influences how frequently a heart muscle cell can be excited. A shorter action potential generally allow a heart muscle cell to be excited more frequently - the refractory period is shorter. The first mechanism, referred to as