What is the primary physiological change seen in dilated cardiomyopathy?

In dilated cardiomyopathy, the primary physiological change is the dilation of the left ventricle. This condition is characterized by an abnormal enlargement of the heart chambers, particularly the left ventricle, which leads to decreased contractility and impaired pumping function. The dilation occurs as a result of a variety of factors, such as genetic predispositions, viral infections, and other underlying health conditions, leading to the weakening of the ventricular walls.

The dilation itself results in an increased end-diastolic volume and a reduction in the efficiency of the heart’s ability to pump blood, which can lead to symptoms of heart failure. While hypertrophy, thinning of the ventricular walls, and fibrosis can occur in various types of heart disease or later on in the course of dilated cardiomyopathy, they are not the defining features of the condition. The hallmark is indeed the enlarged, or dilated, state of the left ventricle, which is fundamental in understanding the pathophysiology and clinical manifestations of dilated cardiomyopathy.