The ventricles – small ventricles can be a normal finding, but occasionally reflect a thickened heart muscle (see below) which leads to an abnormally small chamber. Mildly enlarged (‘dilated’) ventricles can be a normal finding in athletes, but usually reflect early adaptation of the heart’s pumping chambers to another problem, such as a leaky valve. Severely dilated ventricles can be suggestive of heart muscle disease known as ‘dilated cardiomyopathy’ – this diagnosis will require follow-up with a specialist, particularly as the condition runs in families.
The atria – enlarged atria suggest adaptation of the heart’s filling chambers to another abnormality, such as a leaky valve. For example, mitral valve problems can cause severe dilatation of the left atrium; this dilatation itself does not require specific treatment, however the underlying cause may need referral on to a specialist, and large atria can predispose patients to abnormal heart rhythms.