Central sleep apnea (CSA) is not a typical initial manifestation of AVRC, but CSA is often related to congestive heart failure, neurologic disease, end-stage renal failure, or medication (eg, opioid analgesics). CSA is rarely idiopathic and therefore evaluation of underlying causes is strongly recommended in patients who do not have conditions that sufficiently explain the presence of central sleep apnea or Hunter-Cheyne-Stokes respiration. CSA in patients with congestive heart failure can be explained by a prolonged circulation time, low cardiac output, and stimulation of pulmonary J-receptors by pulmonary edema due to left heart failure. CSA is seen primarily in patients with left ventricular systolic heart failure and not isolated right ventricular heart failure, as in this patient, but has been described in patients with right heart failure due to primary pulmonary hypertension. In AVRC, the dilated right ventricle with severely impaired function can cause low-output cardiac failure with reduced pulmonary blood flow, thereby increasing circulation time. The dilated right ventricle can also impair left ventricular diastole function, due to interventricular interactions. Also, replacement of cardiac myocytes by fatty tissue can affect the left ventricle and thereby cause biventricular heart failure.