Cardiomegaly · What Is It, Causes, Treatment, and More

Cardiomegaly refers to the enlargement of the heart. The heart, which sits slightly behind and left of the sternum, is responsible for pumping blood throughout the body. It is made up of two atria, the chambers at the base, and two ventricles in the apex. The septum, a dividing wall of tissue, separates the heart into left and right halves.  

In cardiomegaly, enlargement of the heart can include the entire heart, one side of the heart (i.e., the right or left), or a specific area (i.e., the atria or ventricles).  

Cardiomegaly can develop from a variety of conditions that affect how the heart functions. Certain conditions, such as high blood pressure, can make the heart work harder to pump blood throughout the body. On the other hand, conditions like coronary artery disease and cardiomyopathy can lead to damage of the heart muscle. Regardless, all of these conditions can reduce the heart’s ability to pump bloodefficiently and consequently cause the heart muscle to enlarge, resulting in cardiomegaly.    

In the case of high blood pressure, the heart muscle enlarges because the heart muscle must work harder to overcome the higher pressure and maintain cardiac output. Similarly, pulmonary hypertension, which occurs when there is increased pressure in the pulmonary artery that connects the right side of the heart to the lungs, can also force the heart to pump harder in order to push blood forward, through the lungs, and into the left side of the heart. As a result of the increased exertion, the right side of the heart may enlarge.  

Coronary artery disease, which results from the build-up of plaque in the arteries supplying blood flow to the heart, can result in poor blood flow or blockages, leading to poor tissue perfusion and subsequently ischemia. Prolonged ischemia to these areas can lead to heart muscledamage. In order to compensate for the damaged muscle, the rest of the heart muscle will enlarge so it can continue pumping blood throughout the body. 

Cardiomyopathy, a group of heart conditions that directly affect the heart muscle, also lead to cardiomegaly. The most common types of cardiomyopathy are dilated, restrictive, and hypertrophic cardiomyopathy. In addition, pericarditis, or inflammation of the heart’s pericardium (i.e., the fibrous sac surrounding the heart), can make the heart enlarge.  

Moreover, conditions that do not directly affect the heart can also lead to cardiomegaly. Anemia, which is characterized by low red blood cell counts, may require the heart to pump harder in order to circulate enough oxygen throughout the body. An underactive thyroid (i.e., hypothyroidism) or an overactive thyroid (i.e., hyperthyroidism) can change the heart rate and blood pressure in ways that enlarge the heart. Additionally, excessive iron in the body, or hemochromatosis, can cause cardiomegaly as a result of iron deposition and accumulation in the heart.  

Other risk factors for the development of cardiomegaly include heart valve disease, congenital heart conditions, rare diseases (e.g., amyloidosis), and having a family history of cardiomegaly.  

Treatment of cardiomegaly often begins with lifestyle modifications to address modifiable risk factors. These may include losing weight, increasing exercise, decreasing alcohol consumption, and eating a variety of fruits, vegetables, whole grains, nuts, poultry, and fish, while limiting intake of sodium, red meats, and saturated fats.  

Beyond lifestyle modifications, treatment often involves medication to address the underlying cause. In cases of coronary artery disease, medication may be prescribed to reduce cholesterol levels in the body (e.g., statins, niacin) and keep blood flowing through the arteries (e.g., aspirin). Other prescription medications, like angiotensin-converting enzyme (ACE) inhibitors, can help regulate high blood pressure and help cardiac remodeling in congestive heart failure. Hypertrophic cardiomyopathy treatment usually consists of medications (e.g., beta blockers, calcium channel blockers) that aim to decrease heart rate so the heart can fill and pump blood more effectively. 

If left untreated, cardiomegaly can lead to the development of blood clots, life-threatening arrhythmias, and heart failure. Cardiomegaly can be life-threatening, so diagnosis and treatment is critical.