The warm-up effect protects against ischemic left ventricular dysfunction in patients with angina

• Published in: Journal of the American College of Cardiology Vol. 37; no. 3; pp. 705 - 710
• Main Authors: Kelion, Andrew D, Webb, Terence P, Gardner, Maureen A, Ormerod, Oliver J.M, Banning, Adrian P
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-03-2001; Elsevier Science
• Subjects: Aged; Angina Pectoris - physiopathology; Biological and medical sciences; Cardiology. Vascular system; Coronary heart disease; Electrocardiography; Exercise Test; Female; Heart; Hemodynamics; Humans; Male; Medical sciences; Middle Aged; Myocardial Ischemia - physiopathology; Myocardial Stunning - physiopathology; Radionuclide Angiography; Stroke Volume; Ventricular Dysfunction, Left - physiopathology; ERNA; EF; RPP; EDV; ECG; ESV; LV; Physical exercise; Human; Warming; Pathophysiology; Cardiovascular disease; Heart ventricle; Left ventricular failure; Angina pectoris; Coronary heart disease; Myocardial disease; Vascular disease; Prevention; Ischemia; Heart disease; Myocardium; Complication; Exercise tolerance test; Preconditioning
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(00)01182-7

OBJECTIVES
The goal of this study was to investigate whether the “warm-up” effect in angina protects against ischemic left ventricular (LV) dysfunction.
BACKGROUND
After exercise, patients with coronary disease demonstrate persistent myocardial dysfunction, which may represent stunning, as well as warm-up protection against further angina, which may represent ischemic preconditioning. The effect of warm-up exercise on LV function during subsequent exercise has not been investigated.
METHODS
Thirty-two patients with multivessel coronary disease and preserved LV function performed two supine bicycle exercise tests 30 min apart. Equilibrium radionuclide angiography was performed before, during and up to 60 min after each test. Global LV ejection fraction and volume changes and regional ejection fraction for nine LV sectors were calculated for each acquisition.
RESULTS
Onset of chest pain or 1 mm ST depression was delayed and occurred at a higher rate-pressure product during the second exercise test. Sectors whose regional ejection fraction fell during the first test showed persistent reduction at 15 min (68 ± 20 vs. 73 ± 20%, p < 0.0001). These sectors demonstrated increased function during the second test (71 ± 20 vs. 63 ± 20%, p = 0.0005). The reduction at 15 min and the increase during the second test were both in proportion to the reduction during the first test. Effects on global function were only apparent when the initial response to exercise was considered.
CONCLUSIONS
The warm-up effect is accompanied by protection against ischemic regional LV dysfunction. The degree of stunning and protection after exercise is related to the severity of dysfunction during exercise, consistent with results from experimental models.