The more muscular looking heart
Channel: York Cardiology
Date: 2019-10-25

The heart is a muscle and as with any muscle, when it has to work against a higher pressure over a prolonged period of time, it becomes more muscular. This increased muscle mass  is seen as an increased thickness in the walls of the heart and is known as hypertrophy. Doctors sometimes erroneously refer to this as an enlarged heart. This is not true - the heart is not bigger but it is heavier; the walls are just more muscular and therefore appear thicker than normal. This is why a more muscular heart does not appear abnormal on a chest x-ray. As the left ventricle is the chamber of the heart that pumps blood around the whole of the body, any sustained increase in pressure that the left ventricle works against will result in the development of left ventricular hypertrophy (LVH). SImilarly the right ventricle has to pump blood to the lungs and if it has to do so against a higher pressure for a long time then this will lead to right ventricular hypertrophy (RVH).

What are the causes of hypertrophy
The commonest cause of LVH is hypertension (high blood pressure). Another important cause is a valvular abnormality called aortic stenosis - abnormal narrowing of the aortic valve which controls the outflow of blood from the heart when the heart contracts which results in increasing the work that the heart has to do to pump the blood out.
Common causes of RVH are pulmonary hypertension (increased blood pressure in the pulmonary circulation) and pulmonary stenosis - a rare abnormal narrowing of the the pulmonary valve which controls the outflow of blood from the right heart.