Ventricular arrhythmias in cor pulmonale. The effect of oxygen treatment

: Long-term ECG monitoring was carried out on 36 patients with chronic obstructive airway disease and cor pulmonale. Ventricular extrasystoles were detectable in all patients with greater than 30/h occurring in 13. Multifocal ventricular extrasystoles were seen in 29 patients, couplets in 16, runs in 6 and early (R-on-T) extrasystoles in 8 patients. When the ventricular extrasystoles exceeded 30 per hour the average oxygen partial pressure (paO2), determined in capillary blood, was 59.5 mm Hg, whereas it was higher, 66.4 mm Hg (P less than 0.0125), when there were less than or equal to 30/h. Oxygen (2 l/min) was administered to 13 patients between 20.00 h and 08.00 h and then room-air the following night via a nasal tube. After the administration of oxygen mean paO2 was 72.3 mm Hg and after breathing room-air 62.6 mm Hg (P less than 0.01). During the administration of oxygen, extrasystoles appeared less frequently than after breathing room-air (927 vs 1211; P less than 0.05). These results show that ventricular extrasystoles appear more often with decreasing paO2 and that oxygen therapy can reduce their frequency.