Impact of myocardial salvage assessed by (99m)Tc-sestamibi scintigraphy on cardiac autonomic function in patients undergoing mechanical reperfusion therapy for acute myocardial infarction.
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Oxygen uptake kinetics during and after exercise are useful markers of coronary artery disease in patients with exercise electrocardiography suggesting myocardial ischemia.
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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). METHODS AND 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. (+info)
Cardiac MRI in ischemic heart disease.
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Considerable progress has been made in cardiac magnetic resonance imaging (MRI). Cine MRI is recognized as the most accurate method for evaluating ventricular function. Late gadolinium-enhanced MRI can clearly delineate subendocardial infarction, and the assessment of transmural extent of infarction on MRI is widely useful for predicting myocardial viability. Stress myocardial perfusion MRI allows for detection of subendocardial myocardial ischemia, and the diagnostic accuracy of stress perfusion MRI is superior to stress perfusion single-photon emission computed tomography in patients with multivessel coronary artery disease (CAD). In recent years, image quality, volume coverage, acquisition speed and arterial contrast of 3-dimensional coronary magnetic resonance angiography (MRA) have been substantially improved with use of steady-state free precession sequences and parallel imaging techniques, permitting the acquisition of high-quality, whole-heart coronary MRA within a reasonably short imaging time. It is now widely recognized that cardiac MRI has tremendous potential for the evaluation of ischemic heart disease. However, cardiac MRI is technically complicated and its use in clinical practice is relatively limited. With further improvements in education and training, as well as standardization of appropriate study protocols, cardiac MRI will play a central role in managing patients with CAD. (+info)
Regadenoson induces comparable left ventricular perfusion defects as adenosine: a quantitative analysis from the ADVANCE MPI 2 trial.
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Coronary CT angiography and myocardial perfusion imaging to detect flow-limiting stenoses: a potential gatekeeper for coronary revascularization?
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