Systolic dysfunction is a characteristic of dilated cardiomyopathy (DCM). It is also seen in some patients with hypertrophic cardiomyopathy (HCM) who develop progressive left ventricular dilatation and a decrease in LVEF. In general terms, systolic dysfunction is defined as an LVEF less than 40%. Diastolic dysfunction refers to cardiac dysfunction in which left ventricular filling is abnormal and is accompanied by elevated filling pressures. The diastolic phase of cardiac function includes two components.