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
Heart failure with preserved ejection fraction atrio-ventricular valves open (mitral valve at left side and tricuspid valve at right side) and the blood passes from the atria into the ventricles. First, ventricles are filled by a pressure gradient but near the end, atria contract (atrial kick) and force more blood to pass into ventricles. Atrial contraction is responsible for around 20% of the total filling blood volume. (In atrial fibrillation, this additional 20% filling volume is lost and the patient may experience systolic heart failure symptoms). Complete left ventricular filling is essential to maintain maximum cardiac output. Left ventricular filling is dependent upon ventricular relaxation and