Nocturnal vs diurnal cardiac arrhythmias in patients with chronic obstructive pulmonary disease

Continuous electrocardiograms were recorded from ten patients with chronic obstructive pulmonary disease. During 24 hours of recording, the patients breathed air; and for 24 hours, they breathed oxygen at 2 L/min by nasal cannula. Oxygenation, as monitored by ear oximetric studies and by periodic analysis of arterial blood, showed frequent nocturnal desaturation. Nine patients demonstrated arrhythmias during the monitoring period, and the frequency of premature ventricular contractions was significantly greater at night. Therapy with supplemental oxygen dramatically reduced the frequency of premature ventricular contractions in four patients, but the reduction in frequency of arrhythmias in the total group did not reach statistical significance. These results show that cardiac arrhythmias occur commonly at night during sleep in patients with chronic obstructive pulmonary disease. The data suggest that arterial desaturation may be responsible for some of these arrhythmias.