What is Diastolic Dysfunction?

There are two parts to the pumping action of the heart. The first part is called diastole, when blood collects in the lower heart chambers (right and left ventricles) as it is pushed through the tricuspid and mitral valves.

Once the ventricles are filled with blood, the second part of the pumping action begins. The ventricles contract and blood is pushed from the right ventricle into the pulmonary artery and from the left ventricle into the aortic valves. This part is called systole.

The pathophysiology of diastolic dysfunction
Diastolic dysfunction refers to when the diastole part of this action is abnormal. The ventricles do not properly relax and become stiff meaning they cannot fill with blood properly. This causes blood to “dam up” in other parts of the body.

Pressure in the ventricles then increases as blood from the next heartbeat tries to enter. This leads to extra pressure and fluid building up in the vessels of the lungs (referred to as pulmonary congestion) or in the vessels that lead back to the heart (referred to as systemic congestion).

Pulmonary congestion causes fluid or transudate to leak from these vessels into the lung alveoli, causing pulmonary edema. This condition hampers oxygenation of blood in the lungs, resulting in shortness of breath and (in some instances) even death if the condition is not discovered and treated swiftly.

The systemic congestion has detrimental effects on other organs in the body such as the kidney and liver, as a result of poor organ perfusion. Swelling and congestion may also occur in the legs and within the abdomen.

Diastolic dysfunction is a common problem, with many people aged older than 70 years having the condition. In the majority of cases, the condition is not severe enough to lead to diastolic heart failure.