Abnormal segmental contraction velocity in coronary artery disease produced by isometric exercise and atrial pacing.
Since isometric exercise by sustained handgrip leads to a sizable increase in aortic pressure this maneuver was used in addition to atrial pacing to increase the imbalance between oxygen demand and supply in two groups of patients. Both groups were studied by left heart catheterization and cineangiography in the right anterior oblique projection, at rest, during atrial pacing and during combined pacing and handgrip exercise. Group 1, the control group, consisted of 10 patients without coronary artery disease having an ejection fraction of 0.61 to 0.82. Group 2 was composed of 10 patients with definite obstructive disease of one or more of the three main coronary arteries. At rest, ejection fraction was normal or nearly normal (range 0.54 to 0.78). Regional myocardial contraction performance was assessed by determining mean segmental shortening velocities at the basal (VSB), middle (VSM) and apical (VSA) short ventricular axes. Whereas at rest there was no significant difference between the two groups or any of the three velocities, during pacing, VSM and VSA were significantly smaller in Group 2 than in Group 1 (P smaller than 0.02). During pacing combined with handgrip exercise the difference between the two groups was clearly accentuated, all three velocities being highly significantly decreased in Group 2 (VSB, P smaller than 0.01; VSM and VSA, P smaller than 0.001). When evaluated individually the patients of Group 2 had in 9 segments during pacing values for VSB, VSM and VSA that were below the range of the normal subjects. During pacing combined with handgrip a newly abnormal shortening velocity was observed in 12 segments (VSB abnormal in 3 of 7, VSM in 4 of 7 and VSA in 5 of 7 instances). In conclusion, the combination of atrial pacing and handgrip exercise appears to be a useful stress maneuver to identify temporarily dysfunctioning segments in patients with coronary artery disease in whom atrial pacing alone is not sufficient to induce ischemic contraction disorders.
D000790:Angiocardiography; D001794:Blood Pressure; D002302:Cardiac Output; D002932:Cineangiography; D003327:Coronary Disease / Q000503:physiopathology*; D004558:Electric Stimulation; D005080:Exercise Test; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D010138:Pacemaker, Artificial; D005082:Physical Exertion