What is diastolic dysfunction?
Channel: York Cardiology
Date: 2019-12-20

In this video, Dr Sanjay Gupta discuses diastolic dysfunction. 
The heart is a pump. It has to relax and fill with blood and then contract to push that blood out. The time interval during which the heart contracts is called systole and the period during which it relaxes to fill with blood is called diastole.
For many years, the ability of the heart is measured by its ability to contract and this is best ascertained with echocardiography. Those patients who have hearts which are not able to push blood out of the heart as well as expected are termed as having systolic dysfunction or heart failure and it is well recognised that these patients have a reduced quality of life and life expectancy compared to patients who are able to push blood out as well.

In the search for identifying people at risk of developing systolic dysfunction as early in the disease process as possible, doctors started realising that how much blood the heart pumps out during systole is dependent on how much blood had filled the heart during diastole. In conditions like high blood pressure which often led to systolic dysfunction eventually, it was observed that the heart did not relax as easily and therefore filled with less blood to pump out. These relaxation abnormalities were termed as diastolic dysfunction.

The truth is that there is no such thing as isolated diastolic dysfunction although many medics seem to think there is. Systole and diastole are both phases of the same cardiac cycle and therefore abnormality in one phase will affect the other phase. This is a fundamental law in cardiology called starling’s law. The heart is a 3-dimensional structure which contracts radially, longitudinally and also twists. The test we use to assess the systolic function is echocardiography which looks at the heart in 2 dimensions and doesn’t routinely assess for longitudinal or twisting function and therefore the systolic function may look normal. It seldom is normal. 

WHen we use blood tests like BNP which give us an assessment of how much pressure is within the heart, we find BNP levels are raised in patients with diastolic dysfunction and echocardiographically ‘normal’ systolic function.

Diastolic dysfunction is often caused by ageing, high blood pressure, diabetes, and excessive weight. If left unaddressed it may progress to echocardiographically detected systolic dysfunction. There are no particular tablets as such which will reverse it. The more important thing is to control the risk factors that may have caused it in the first place. This includes weight loss, lifestyle modification and regular exercise and control of blood pressure, diabetes and sleep apnoea.