In which condition is the heart characterized by eccentric hypertrophy?

Eccentric hypertrophy is characterized by an increase in the size of the heart chambers, primarily the ventricles, with a proportional increase in ventricular wall thickness. This adaptive response often occurs in conditions where there is volume overload, leading to an expansion of the heart's internal dimensions.

In dilated cardiomyopathy (DCM), the ventricles become dilated and the myocardial fibers stretch, resulting in a larger ventricular volume and subsequent eccentric hypertrophy. This is often secondary to factors like chronic volume overload from valvular regurgitation or myocardial damage, which leads to reduced contractility and compensatory chamber enlargement.

While hypertrophic cardiomyopathy (HCM) does involve hypertrophy of the heart muscle, it features concentric hypertrophy, where the wall thickness increases while the chamber size may not significantly change. Restrictive cardiomyopathy is characterized by stiff heart walls that impede filling rather than enlargement of the chambers. Left ventricular hypertrophy typically occurs in response to pressure overload conditions and is characterized by concentric hypertrophy as well.

Thus, among the given options, dilated cardiomyopathy is the condition that best illustrates eccentric hypertrophy of the heart.