Nocturnal oxygen and ventricular arrhythmias during Cheyne-Stokes respiration in patients with congestive heart failure

Cheyne-Stokes respiration (CSR) is common during sleep in patients with severe congestive heart failure. It is not clear, if there is a relation between CSR and arrhythmias. Therefore in this study the impact of the nocturnal CSR on ventricular arrhythmias and the heart rate, as well as the influence of nasal nocturnal oxygen on CSR and sleep was studied. In a randomized, double-blind, crossover study 22 patients were assigned to 1 week each of oxygen and room air. The age of the patients was 57 ± 10 years. Their mean left ventricular ejection fraction was 18.9 ± 6.4%. Breathing oxygen significantly reduced the duration of CSR by over 50% (162 ± 142 vs 88 ± 106 min, p < 0.05). Sleep did improve as evidenced mainly by less arousals (21 ± 13 vs 15 ± 9/h total sleep time; p < 0.05) and stage 1 sleep as well as more stage 2 and slow wave sleep. Nocturnal oxygen resulted in a reduction of ventricular arrhythmias for ventricular ectopic beats (53.1 ± 157.7 vs 44.7 ± 97.1/h), couplets (9.0 ± 38.3 vs 3.7 ± 14.3/h) and tachycardias (1.8 ± 7.2 vs 0.4 ± 0.8/h). Due to the high day-to-day variability these differences were not significant, but the decrease of average nocturnal heart rate with oxygen was (71 ± 14 vs 68 ± 14/min; p < 0.05). In conclusion, nocturnal oxygen causes a reduction of CSR, an improvement of sleep and a decrease of arousals. A significant reduction of arrhythmias by nocturnal oxygen could not be proved.