Diyastolik refers to the phase of the cardiac cycle when the heart's chambers, particularly the ventricles, relax and fill with blood. This phase is crucial for ensuring that the heart has enough blood to pump out during the next contraction. Proper diastolic function is essential for maintaining adequate blood flow and overall cardiovascular health. During diastolic filling, the heart receives blood from the atria, which have just contracted. The mitral and tricuspid valves open, allowing blood to flow into the ventricles. Any issues with diastolic function can lead to conditions such as heart failure, where the heart struggles to fill properly, impacting its ability to pump effectively.