Cardiac Resynchronization Therapy Altered the Severity and Pattern of Sleep Disordered Breathing in Case of Heart Failure with Systolic Dysfunction

69-year-old men with heart failure (HF) due to dilated cardiomyopathy (DCM) was referred for cardiac resynchronization therapy (CRT). He has frequent episodes of hospitalizations for acute decompensated heart failure (ADHF), requiring catecholamine-administration. He has functional class III-IV symptoms, AF with complete left bundle branch block (CLBBB) in electrocardiogram, and left ventricular ejection fraction (LVEF) of 20% in echocardiography. Considering previous history of ventricular tachycardia (VT), CRT with defibrillator (CRT-D) was implanted. After implantation, dyssynchrony ameliorated with an improvement of functional class (to II-III) and a reduction of BNP levels (from 3,000 to 800 pg/ml). Besides, apnea-hypopnea index in polysomnography reduced from 82.0/hr to 18.7/hr with an alteration of type of sleep disordered breathing (SDB) from predominant central sleep apnea (CSA) which required adaptive servo-ventilation (ASV) as a treatment to obstructive sleep apnea which was sufficiently suppressed by continuous positive airway pressure (CPAP). Use of ASV for HF patients with predominant CSA has been limited because of negative and potentially harmful results from current clinical trial. This case reminds us to reevaluation of SDB or reconsideration of treatment option for SDB following CRT-D implantation in HF with reduced ejection fraction and predominant CSA.