Heart Failure Overview: heart attack, heart pumping, heart no oxygen, classifying heart failure, HFrEF, HFpEF

Heart Failure - What it is

Heart failure (also known as congestive heart failure) happens when the heart becomes weak or stiff, thus losing its ability to pump enough blood. This causes a build-up of fluid in the tissues (an oedema), leaving the organs and tissues with insufficient oxygen and nutrients to function properly. With lifestyle modifications and medications, the heart can pump blood better.

heart failure conditions & treatments

While heart failure can occur at any age, it tends to occur more frequently in elderly patients. In comparison to the Western population, the onset of heart failure in Singapore occurs at a younger age. In Singapore, the average age of onset for heart failure is at 50 years old, as compared to 60 years old in the West. A significant number of heart failure patients also have pre-existing medical conditions such as diabetes mellitus.

Classifying Heart Failure

The heart function is determined by its ejection fraction and diastolic function. Ejection fraction is a measure of the percentage of blood leaving the left ventricle of the heart each time it contracts to supply the vital organs, while diastolic function is the measure of heart muscle relaxation to allow it to fill with blood. The assessment of the heart function can be performed using transthoracic echocardiogram or cardiac magnetic resonance imaging (CMR).

There are different types of heart failure, whereby heart failure can be classified into two main groups.

1) Heart failure with reduced ejection fraction (HFrEF)

This occurs when the left ventricle does not contract effectively and less blood is pumped out to the body compared to a normal functioning heart.

In HFrEF (also known as systolic heart failure), the pump function of the heart is weakened and the organs do not receive enough oxygen. Patients usually have a left ventricle ejection fraction of less than 40% and this could be due to other factors, including coronary artery disease, infections, medications and hereditary conditions.

2) Heart failure with preserved ejection fraction (HFpEF)

This occurs when the heart muscle contracts normally, however, the left ventricle is not able to relax and properly fill with blood during ventricular filling, resulting in ineffective pumping of blood around the body.

In HFpEF (also known as diastolic heart failure), the systolic heart function is normal (left ventricle ejection fraction of 50% and above), however the heart muscle is stiff. Consequently, there is ineffective filling up and pumping of blood around the body. Stiffness of the heart muscle can occur due to a variety of reasons such as ageing, long-standing high blood pressure or obesity.