| Abstract: | We conducted a single-bind placebo controlled study using 24-hour continuous ambulatory electrocardiographic recordings. The arrhythmogenic potential of the combination of salbutamol and theophylline was investigated in 25 ambulatory subjects with severe chronic airflow obstruction (mean age 65 +/- 8 SD, mean FEV1 31 percent +/- 13 SD predicted). Asymptomatic arrhythmias were very prevalent in the study population: 76 percent of the patients had runs of supraventricular tachycardia while 24 percent had runs of ventricular tachycardia. Individual arrhythmia frequency showed greater between-test variability than previously described in non-COPD subjects. The mode of administration of salbutamol may have affected arrhythmia frequency in that subjects using aerosol nebulizers had more ventricular extrasystoles than those using metered dose inhalers. Although the addition of theophylline to salbutamol significantly increased heart rate and supraventricular extrasystoles, there was no statistically significant increase in ventricular arrhythmias. |
