Effects of low-level carbon monoxide exposure on resting and exercise-induced ventricular arrhythmias in patients with coronary artery disease and no baseline ectopy.

The effects of acute elevation of carboxyhemoglobin (COHb) concentrations on resting and exercise-induced ventricular arrhythmias were evaluated in 10 patients who had ischemic heart disease and in whom no ectopy during baseline monitoring was noted. After an initial training session, patients were exposed to air, 100 ppm carbon monoxide (CO), or 200 ppm CO on successive days in a randomized, double-blind, cross-over fashion. After exposure to 100 and 200 ppm CO, venous COHb levels averaged 4% and 6%, respectively. Symptom-limited supine exercise was performed after exposure. Eight of the 10 patients had evidence of exercise-induced ischemia--either angina, 1.0 mm ST depression, or abnormal ejection fraction response--during 1 or more exposure days. Ambulatory electrocardiograms were obtained on each day and analyzed for arrhythmia frequency and severity. On air and CO exposure days, each patient had only 0-1 ventricular premature beat/h in the 2 h prior to exposure, during the exposure period, during the subsequent exercise test, and in the 5 h following exercise. In conclusion, low-level CO exposure is not arrhythmogenic in patients with coronary artery disease and no ventricular ectopy at baseline.

RCT Entities:   Population Interventions Outcomes