Cardiomegaly and cardiomyopathy: Cardiomegaly refers to an enlarged heart seen on a chest x-ray or other imaging test. It is not a disease in and of itself but is generally a symptom of another condition. This condition can be temporary as a result of stress from pregnancy or a medical condition. There are various things that can cause the heart muscle to thicken or its chamber to dilate and cause an enlarged heart.
Cardiomyopathy is a general term used to refer to diseases of the heart. There are three main types of cardiomegaly: dilated cardiomyopathy, hypertrophic cardiomyopathy, and restrictive cardiomyopathy.
Continue reading to learn more about cardiomegaly and cardiomyopathy.
The average weight of a normal adult heart is approximately 11 ounces. When the size of the heart exceeds this, cardiomegaly occurs.
There can be various causes of cardiomegaly including:
Dilated cardiomyopathy occurs with overall dilation of the heart chambers, particularly the ventricles. This dilation is an indication of a weakness in the heart muscle and an inability for the heart to pump blood properly. In dilated cardiomyopathy, the weakness affects all parts of the muscular tissues of the heart.
The heart enlarges in order to compensate for the weakness and lack of blood flow. Dilated cardiomyopathy results in heart failure and improper blood flow to tissues and organs which, if left untreated, can cause excessive fluid retention, swelling of the legs, congestion in the lungs and liver and more serious heart conditions.
This type of cardiomyopathy involves an abnormal growth of the heart muscle fibers that can restrict blood flow in and out of the heart. All of the chambers of the heart are affected as their walls thicken, but the left ventricle generally thickens the most.
It is very common in hypertrophic cardiomyopathy for the septum, the wall that separates the right and left ventricles, to be asymmetrically enlarged, thereby trapping blood inside the heart and creating inadequate blood flow to the brain and other organs.
This type of cardiomyopathy is also referred to as idiopathic hypertrophic subaortic stenosis or IHSS. The overgrowth of the heart causes a bulge to protrude into the ventricular chamber impeding the flow of blood into the aorta and out to the rest of the body. The cause of hypertrophic cardiomyopathy is generally unknown.
This type of cardiomyopathy is less common than the other two and results from the heart not being able to expand and contract properly. It can be caused by abnormal material entering the heart such as amyloidosis (a build-up of the protein amyloid in the heart) or the formation of fibrous tissue. Like hypertrophic cardiomyopathy, the cause of restrictive cardiomyopathy is not well known.
A patient with cardiomegaly may initially feel no symptoms at all in the beginning.
Symptoms generally worsen as time goes on and depending upon the gravity of the problem can be mild or severe.
Treatment of cardiomyopathy depends upon the underlying cause. For causes such as excessive alcohol consumption or nutritional deficiency, the treatment may be as simple as cutting out alcohol and improving nutrition. However, in a large percentage of cases, the cause is unknown. Therefore, physicians generally focus on relieving symptoms and trying to improve the heart's ability to properly pump blood to the body.
Medications are also administered in order to improve the ability of the heart muscle to function properly. These type of drugs, Digitalis being the most well known, work by increasing calcium levels inside of the heart's cells and causing the heart muscle to contract. Calcium channel blockers such as verapamil are also very effective in treating symptoms resulting from cardiomyopathy.
If needed, stronger cardiac stimulants such as dopamine, dobutamine, and amrinone may be given, although these are generally only used in a hospital setting. Beta blockers may also be given to prevent a rapid heartbeat and strong contractions and antiarrhythmic drugs may also be administered in the case of irregular heart rhythms.
Patients will also be required to limit strong physical activity that can cause stress.