Harvard Heart Letter

Ask the doctor: What does an enlarged heart signify?

Ask the doctor

What does an enlarged heart signify?

Q. My doctor told me I have an enlarged heart. What is this? What causes it and what does it mean for my health?

A. The term "enlarged heart" refers to a heart that is larger than average for the age and size of its owner. It can mean many things, and not all of them are worrisome.

An enlarged heart is typically spotted on a routine chest x-ray that shows the heart's shadow to be larger than it should be relative to the size of the person's chest. The difference between normal and enlarged isn't necessarily huge. For an average-size person, the left ventricle might measure 2 inches in diameter; 2.5 inches would be abnormally large. Sometimes an electrocardiogram tracing suggests the heart is enlarged. The most accurate methods of determining the size of the heart are the echocardiogram and magnetic resonance imaging. These techniques can measure the size of each heart chamber down to about a millimeter.

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