Related Experiment Video
Updated: Feb 27, 2026
Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Clinical, scintigraphic, and angiographic predictors of oxygen pulse abnormality in patients undergoing
Andrea De Lorenzo1, Carlito Lessa da Silva1, Fernando Cesar Castro Souza1
1Federal University of Rio de Janeiro, National Institute of Cardiology, Instituto Estadual de Cardiologia Aloysio de Castro, Rio de Janeiro, Brazil.
Background:
The oxygen (O2 ) pulse curve obtained at cardiopulmonary exercise testing provides information on cardiorespiratory fitness and the presence of cardiovascular disease. O2 pulse abnormalities have been attributed to myocardial ischemia, among other conditions, but the predictors of abnormal O2 pulse curves are not completely known.
Hypothesis:
Perfusion abnormalities detected by myocardial perfusion scintigraphy (MPS) may be associated with abnormal O2 pulse curves.
Methods:
Forty patients with normal left ventricular function underwent cardiopulmonary exercise testing with radiotracer injection at peak exercise, followed by MPS. The O2 pulse curves were classified as (A) normal; (B) probably normal (normal slope with lower peak value); (C) probably abnormal (flat, with low peak value); or (D) definitely abnormal (descending slope), and analyzed as A/B vs C/D. Coronary artery disease (CAD) was defined as >50% stenosis. MPS perfusion scores were calculated (summed rest score [SRS], indicating myocardial fibrosis; summed difference score, indicating ischemia).
Results:
Comparing patients with A/B vs C/D curves, the latter were more frequently female and had higher SRS. The prevalence of ischemic MPS, of any CAD, or multivessel CAD was not significantly different among patients with A/B or C/D curve patterns. On logistic regression, female sex, body mass index, and the SRS were significantly associated with C/D curves.
Conclusions:
Female sex, increasing body mass index, and myocardial fibrosis were significant predictors of abnormal O2 pulse curves. Myocardial ischemia and the presence and extent of CAD were not associated with the abnormal patterns of the O2 pulse curve.
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