David S. Sheps, MD, MSPH; Margaret C. Herbst, MSN; Alan L. Hinderliter, MD; Kirkwood F. Adams, MD; Lars G. Ekelund, MD, PhD; John J. O'Neil, PhD; George M. Goldstein, PhD; Philip A. Bromberg, MD; Janice L. Dalton, BS; Martha N. Ballenger; Sonia M. Davis, MS; Gary G. Koch, PhD
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.
Sheps DS, Herbst MC, Hinderliter AL, Adams KF, Ekelund LG, O'Neil JJ, et al. Production of Arrhythmias by Elevated Carboxyhemoglobin in Patients with Coronary Artery Disease. Ann Intern Med. ;113:343–351. doi: 10.7326/0003-4819-113-5-343
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Published: Ann Intern Med. 1990;113(5):343-351.
Cardiology, Coronary Heart Disease, Rhythm Disorders and Devices.
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