Figure 1. Schematic representation of changes in the cardiac chambers of an individual with HHD compared with idiopathic or ischemic cardiomyopathy.

The main difference between HHD and the other two main causes of heart failure (ischemic heart disease associated with prior myocardial infarction[s] and idiopathic dilated cardiomyopathy) is the nature of the geometric remodeling of the LV chamber. Patients with HHD usually present with LVH but with a normal-sized LV chamber and preserved systolic function. By contrast, patients with heart failure secondary to ischemia or idiopathic cardiomyopathy usually have an enlarged, dilated LV chamber and more frequently also have RV enlargement.