What is diastole of the heart?

As a cardiac specialist with extensive experience in the field of cardiology, I can provide a detailed explanation of the diastole of the heart. Diastole refers to the phase of the cardiac cycle when the heart muscle is in a state of relaxation. This allows the heart to fill with blood from the veins. There are two types of diastole: ventricular and atrial. Ventricular diastole is the period during which the two ventricles are relaxing from the contortions of contraction, then dilating and filling. This phase is crucial because it is when the ventricles, the lower chambers of the heart, are at their largest volume and are able to receive the maximum amount of blood from the atria, the upper chambers of the heart. Atrial diastole is the period during which the two atria likewise are relaxing, dilating, and filling. This occurs after the atria have contracted and pushed blood into the ventricles. The atrial diastole is when the atria are refilling with blood from the veins, preparing for the next contraction. The diastolic phase is essential for maintaining a regular heartbeat and ensuring that the heart can efficiently pump blood throughout the body. It is also during this phase that the heart's electrical activity is reset in preparation for the next contraction, which is known as systole.

Ventricular diastole is the period during which the two ventricles are relaxing from the contortions of contraction, then dilating and filling; atrial diastole is the period during which the two atria likewise are relaxing, dilating, and filling.