Understanding Right Ventricular Hypertrophy (RVH)
Right ventricular hypertrophy (LVH), or LV mass, is a condition where the heart’s right side grows larger than its left side. There are many different types of RVH, but they all share common features such as:
Large size of the heart muscle – usually over 50% bigger than normal; or Large diameter of the heart muscle – usually greater than 20%.
The heart muscle is called the myocardium. Myocardial tissue surrounds the heart and contains most of the cells that make up your body. The heart muscle is made up of two main groups: cardiomyocytes which produce the electrical impulses that control when your muscles contract, and atria which pump blood through your arteries to get oxygenated to your tissues.
Cardiac muscle growth occurs because of an increase in both myocyte number and diameter.
Cardiomyocytes grow by dividing. When they divide, each cell divides into two daughter cells. These daughter cells then continue to divide until there are thousands of them.
Each new generation of cardiac muscle cells starts from a stem cell that has been reprogrammed to become a myocyte rather than a fibroblast (a type of non-muscle cell). A myocyte is the smallest form of human muscle and contains only around 100,000 muscle fibers. When myocytes are no longer able to divide, they begin to grow in length by adding sarcomeres. A sarcomere is a segment of a myocyte that contains the proteins actin and myosin, which are responsible for muscle contraction.
The cells in the left ventricle are smaller because they don’t have to generate as much force for their smaller chamber.
Sources & references used in this article:
Anatomy of the crista supraventricularis: its importance for understanding right ventricular function, right ventricular infarction and related conditions by TN James – Journal of the American College of Cardiology, 1985 – onlinejacc.org
PET imaging may provide a novel biomarker and understanding of right ventricular dysfunction in patients with idiopathic pulmonary arterial hypertension by S Bokhari, A Raina, E Berman Rosenweig… – Circulation …, 2011 – Am Heart Assoc
Regional myocardial blood flow in lambs with concentric right ventricular hypertrophy by JP Archie, DE Fixler, DJ Ullyot, GD Buckberg… – Circulation …, 1974 – Am Heart Assoc