CLINICAL-SIGNIFICANCE OF SLEEP-RELATED BREATHING DISORDERS AFTER IMPLANTATION OF A CARDIOVERTER-DEFIBRILLATOR IN PATIENTS WITH CARDIAC DISEASE AND A HISTORY OF SUSTAINED VENTRICULAR TACHYARRHYTHMIAS

The purpose of our study was to determine the prevalence of sleep rela ted breathing disorders (SRBD) in patients with an implantable cardiov erter-defibrillator (ICD) and to evaluate prospectively the possible i nfluence of SRBD on arrhythmia recurrence and circadian arrhythmia var iation as well as on cardiac mortality during long-term follow-up. For ty consecutive ICD recipients with cardiac disease and a documented hi story of spontaneous, life-threatening, ventricular tachyarrhythmias u nderwent full-night polysomnography and were followed for 2 years. In 16 of 40 patients (40 %), SRBD were diagnosed (Apnea/Hypopnea Index (A HI) > 10); in 9 of these 16 patients (56 %) central sleep apneas (CSA) occurred (in 8 of these 9 patients in combination with Cheyne-Stokes respiration). Seven of the 16 patients with SRBD (44 %) revealed obstr uctive sleep apneas (OSA). AHI was 32 +/- 15 (12-60) in patients with CSA and 32 +/- 27 (11-86) in patients with OSA. Patients with and with out SRBD were comparable concerning left ventricular ejection fraction , NYHA classification, cardiac disease, ICD indication, and concomitan t medication. ICD registered ventricular tachyarrhythmias occurred in 10 of 24 patients (42 %) without SRBD, in 4 of 9 patients (44 %) with CSA, and in 3 of 7 patients (44 %) with OSA. The numbers and circadian variation of episodes registered during follow-up in patients without SRBD, with OSA or CSA were comparable (14 +/- 25, median 4 vs 15 +/- 15, median 7 vs 4 +/- 5, median 2.5). The 2-year cardiac mortality was highest in patients with CSA (4/9 (44 %) vs. 0/7 patients (0 %) with OSA vs 3/24 patients (12.5 %) without SRBD. Thus, the prevalence of SR BD in patients with chronic heart failure and a history of malignant v entricular tachyarrhythmias is high (40 %) and the occurrence of CSA s eems to be predictive for cardiac mortality in these patients. An infl uence of moderate SRBD on arrhythmia recurrence and circadian variatio n of spontaneous sustained tachyarrhythmic events could not be demonst rated.