Production of arrhythmias by elevated carboxyhemoglobin in patients with coronary artery disease

Ann Intern Med. 1990 Sep 1;113(5):343-51. doi: 10.7326/0003-4819-113-5-343.


Objective: To assess the effects of exposure to 4% and 6% carboxyhemoglobin on ventricular arrhythmias in patients with coronary artery disease.

Design: Randomized, double-blind, crossover design.

Setting: Exercise laboratory with an environmentally controlled exposure.

Patients: Forty-one nonsmokers with documented coronary artery disease.

Intervention: On day 1, a training session with no exposure, the baseline carboxyhemoglobin level was measured, and a supine bicycle exercise test was done. On days 2 to 4, patients were exposed to room air, 100 ppm carbon monoxide (target, 4% carboxyhemoglobin) or 200 ppm carbon monoxide (target, 6% carboxyhemoglobin), and they then did supine bicycle exercise with radionuclide ventriculography. Ambulatory electrocardiogram recordings were made during the 4 consecutive days to determine the frequency of ventricular premature depolarization (VPD) at various intervals.

Measurements and main results: The frequency of single VPD/h was significantly greater on the 6% carboxyhemoglobin day than on the room air day during the exercise period (167.72 +/- 37.99 for 6% carboxyhemoglobin compared with 127.32 +/- 28.22 for room air, P = 0.03). During exercise, the frequency of multiple VPD/h was greater on the 6% carboxyhemoglobin day compared with room air (9.59 +/- 3.70 on the 6% carboxyhemoglobin compared with 3.18 +/- 1.67 on room air, P = 0.02). Patients who developed increased single VPD during exercise on the 6% carboxyhemoglobin day were significantly older than those who had no increased arrhythmia, whereas patients who developed complex arrhythmias were also older and, in addition, exercised longer and had a higher peak workload during exercise.

Conclusion: The number and complexity of ventricular arrhythmias increases significantly during exercise after carbon monoxide exposure producing 6% carboxyhemoglobin compared with room air but not after exposure producing 4% carboxyhemoglobin.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Age Factors
  • Aged
  • Air Pollutants / adverse effects*
  • Arrhythmias, Cardiac / blood
  • Arrhythmias, Cardiac / diagnostic imaging
  • Arrhythmias, Cardiac / etiology*
  • Carbon Monoxide / adverse effects*
  • Carboxyhemoglobin / metabolism*
  • Clinical Protocols
  • Coronary Disease / blood*
  • Coronary Disease / complications
  • Coronary Disease / diagnostic imaging
  • Double-Blind Method
  • Exercise Test / drug effects
  • Female
  • Hemodynamics / drug effects
  • Humans
  • Male
  • Middle Aged
  • Radionuclide Ventriculography
  • Random Allocation
  • Time Factors


  • Air Pollutants
  • Carbon Monoxide
  • Carboxyhemoglobin