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Cardiomegaly
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Cardiomegaly means an enlarged heart, and it is an imaging finding rather than a disease. Here is how it is measured: on a posteroanterior chest X-ray .. taken from back to front .., or on a CT scan, the width of the heart's shadow .. the cardiac silhouette .. is compared with the width of the chest. If the heart takes up half or more, that is cardiomegaly.
The heart reaches that size through changes that usually go together: dilated hypertrophy, which is a thickened wall and a stretched chamber at the same time; fibrosis, which is muscle replaced by scar tissue; and contractile failure, which is muscle that no longer squeezes the way it should. Inside each heart cell, the cardiomyocyte, inflammatory signaling is switched on by mechanical stretch, neurohormones .. the hormones that circulate in the blood .. and oxidative stress.
That is why, most of the time, it is not the underlying problem but the mark left by another one. And it is not always the same chamber that enlarges: it can be the right ventricle, the left one, or the atria.
Something that surprises people: many with cardiomegaly feel absolutely nothing. Symptoms on their own are not enough to say whether it is there or not; you need imaging.
In brief
Cardiomegaly is present when the cardiac silhouette measures half or more of the chest's transverse diameter on a posteroanterior radiograph or CT.
It is a measurement on the film: the heart takes up half the chest's width.
Dilated hypertrophy, fibrosis and contractile failure predominate; stretch, neurohormones and oxidative stress drive inflammatory signaling in the cardiomyocyte.
It is usually the manifestation of another disease; what enlarges may be a ventricle or the atria.
Many people with cardiomegaly have no symptoms, and symptoms alone cannot diagnose it.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingCardiomegaly, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated