Allred E N, Bleecker E R, Chaitman B R, Dahms T E, Gottlieb S O, Hackney J D, Pagano M, Selvester R H, Walden S M, Warren J
Health Sciences Computing Facility, Harvard University School of Public Health, Boston, MA.
Environ Health Perspect. 1991 Feb;91:89-132. doi: 10.1289/ehp.919189.
The purpose of this study was to determine whether low doses of carbon monoxide (CO) exacerbate myocardial ischemia during a progressive exercise test. The effect of CO exposure was evaluated using the objective measure of time to development of electrocardiographic changes indicative of ischemia and the subjective measure of time to onset of angina. Sixty-three male subjects (41-75 years) with well-documented coronary artery disease, who had exertional angina pectoris and ischemic ST-segment changes in their electrocardiograms, were studied. Results from three randomized, double-blind test visits (room air, low and high CO) were compared. The effect of CO exposure was determined from the percent difference in the end points obtained on exercise tests performed before and after a 1-hr exposure to room air or CO. The exposures resulted in postexercise carboxyhemoglobin (COHb) levels of 0.6% +/- 0.3%, 2.0% +/- 0.1%, and 3.9% +/- 0.1%. The results obtained on the 2%-COHb day and 3.9%-COHb day were compared to those on the room air day. There were 5.1% (p = 0.01) and 12.1% (p less than or equal to 0.0001) decreases in the time to development of ischemic ST-segment changes after exposures producing 2.0 and 3.9% COHb, respectively, compared to the control day. In addition, there were 4.2% (p = 0.027) and 7.1% (p = 0.002) decreases in time to the onset of angina after exposures producing 2.0 and 3.9% COHb, respectively, compared to the control day. A significant dose-response relationship was found for the individual differences in the time to ST end point and angina for the pre- versus postexposure exercise tests at the three carboxyhemoglobin levels. These findings demonstrate that low doses of CO produce significant effects on cardiac function during exercise in subjects with coronary artery disease.
本研究的目的是确定在递增运动试验期间，低剂量一氧化碳（CO）是否会加重心肌缺血。通过心电图出现缺血性改变的时间这一客观指标以及心绞痛发作时间这一主观指标，来评估一氧化碳暴露的影响。对63名年龄在41 - 75岁、有明确记录的冠状动脉疾病、患有劳力性心绞痛且心电图有缺血性ST段改变的男性受试者进行了研究。比较了三次随机、双盲试验访视（室内空气、低剂量CO和高剂量CO）的结果。一氧化碳暴露的影响通过在暴露于室内空气或CO 1小时前后进行的运动试验中获得的终点指标的百分比差异来确定。暴露后运动后的碳氧血红蛋白（COHb）水平分别为0.6%±0.3%、2.0%±0.1%和3.9%±0.1%。将2% COHb日和3.9% COHb日获得的结果与室内空气日的结果进行比较。与对照组相比，产生2.0%和3.9% COHb暴露后，缺血性ST段改变出现时间分别减少了5.1%（p = 0.01）和12.1%（p≤0.0001）。此外，与对照组相比，产生2.0%和3.9% COHb暴露后，心绞痛发作时间分别减少了4.2%（p = 0.027）和7.1%（p = 0.002）。在三个碳氧血红蛋白水平下，暴露前与暴露后运动试验中，ST段终点时间和心绞痛发作时间的个体差异存在显著的剂量 - 反应关系。这些发现表明，低剂量的CO对患有冠状动脉疾病的受试者运动期间的心脏功能有显著影响。
