CAN SLEEP-DISORDERED BREATHING BE AN INDEPENDENT PREDICTOR OF MALIGNANT VENTRICULAR ARRHYTHMIAS IN PATIENTS WITH HEART FAILURE?

Abstract

Background: Sleep-disordered breathing (SDB) is common and increases mortality rate independently in patients with heart failure (HF). Furthermore, current research suggests that SDB might be an independent predictor of life-threatening ventricular arrhythmias. However, it is still unknown whether SDB have a role to play in electrophysiological background in patient with HF. We assessed the hypothesis that SDB plays an important role in electrophysiological background and contributes to the risk of life-threatening ventricular arrhythmia in patients with HF. Methods: We performed both sleep study and electrophysiologic study in consecutive 33 HF patients and analyzed the relationship between SDB and electrophysiologic data such as AV conduction, ventricular effective refractory period and the inducibility of sustained ventricular tachycardia or fibrillation. All patients had an ejection fraction <40% and spontaneous nonsustained ventricular tachycardia, but no history of cardiac arrest. SDB was defined as an apnea-hypopnea index >10 events/hour on the sleep study. Results: SDB was diagnosed in 22 of 33 patients (67%). There were no statistical differences between patients with and without SDB in baseline characteristics with respect to age, male gender, NYHA class, left ventricular ejection fraction, underlying cardiac disease and medications. AV nodal conduction and ventricular effective refractory period were not significantly differences among two groups. However, the induciblity of ventricular tachyarrhythmia was significantly higher in patients with SDB than those without SDB (73%vs.27%, p=0.013). Conclusions: The present study suggests that SDB can be a risk factor of malignant ventricular arrhythmias without affecting ventricular refractory period in patients with HF.