Oxygen uptake kinetics during and after exercise are useful markers of coronary artery disease in patients with exercise electrocardiography suggesting myocardial ischemia.
BACKGROUND
The aim of the current study was to determine if the slowed exercise oxygen uptake (VO(2)) kinetics, which is developed by myocardial ischemia, would be accompanied by delayed recovery VO(2) kinetics in patients with coronary artery disease (CAD).


RESULTS
Thirty-seven patients with significant ST depression during treadmill exercise underwent cardiopulmonary exercise testing with cycle ergometer. Measurements performed are the ratios of change in increase in oxygen (O(2)) uptake relative to increase in work rate (DeltaVO(2)/DeltaWR) across anaerobic threshold (AT) and 1 mm ST depression point (ST-dep), the time constants of VO(2) during recovery (T(1/2) VO(2)), stress radio-isotope scintigraphy and coronary angiography. Patients were divided into CAD positive (CAD+) and CAD negative (CAD-) groups, based on coronary angiography. In CAD+, DeltaVO(2)/DeltaWR decreased above AT and ST-dep, in contrast to CAD- patients. The T(1/2) VO(2) in CAD+ (103.1 +/-13.0 s) was greater than that of CAD- (76.5 +/-8.7 s) and showed negative correlations to the ratios of DeltaVO(2)/DeltaWR across AT and ST-dep. These parameters improved in the patients who underwent coronary bypass surgery.


CONCLUSIONS
Exercise and recovery VO(2) kinetics were slowed when myocardial ischemia was provoked by exercise. Measurement of exercise and recovery VO(2) kinetics improve the accuracy of the exercise electrocardiogram diagnosis of CAD.
Tajima
Akihiko
A
The Cardiovascular Institute, Graduate School of Health Sciences Tokyo Medical and Dental University, Japan. tajima@cepp.ne.jp
Itoh
Haruki
H
Osada
Naohiko
N
Omiya
Kazuto
K
Maeda
Tomoko
T
Ohkoshi
Nobuyuki
N
Kawara
Tokuhiro
T
Aizawa
Tadanori
T
Wasserman
Karlman
K
D000328:Adult; D000368:Aged; D015308:Anaerobic Threshold; D015415:Biomarkers / Q000378:metabolism; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D023921:Coronary Stenosis / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism / Q000601:surgery; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D055414:Myocardial Perfusion Imaging; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D011659:Pulmonary Gas Exchange; D020127:Recovery of Function; D012720:Severity of Illness Index; D016896:Treatment Outcome
D015415:Biomarkers; D010100:Oxygen