Broadly classified, there are two types of heart failure
1. Systolic heart failure
2. Diastolic heart failure
Systolic heart failure is a condition where the heart becomes a weak pump. It is unable to pump blood into the body because the muscle is weak. The heart chambers move slowly and the cavity of the heart becomes large.
Diastolic heart failure is a condition where the heart muscle becomes stiff but is able to pump normally. The stiff heart muscle does not allow enough blood to fill up the heart when it is relaxing. Due to this, the quantity of blood that is subsequently pumped out is less.
Another classification that is often used by cardiologists is based on the value of the ejection fraction. I have described the types in the box below.
Heart failure with reduced ejection fraction is a term used to describe a heart that has an ejection fraction of less than 40%. In patients in whom it is between 30-40%, it is called moderately impaired left ventricular function.
In patients in whom the ejection fraction is less than 30%, it is called severely impaired left ventricular function. This means that the heart muscle function has been severely damaged.
Given that the heart function is normally above 50-55%, people with values between 41-50% have mildly reduced ejection fraction.
Bear in mind that while these are numbers determined through an echocardiogram, not everyone with a severely reduced ejection fraction will have symptoms. Similarly, patients with mildly reduced ejection fraction can have breathing difficulty.
Treatment is often prescribed based on both echocardiography findings and symptoms.