title: Multiple-lead QRS changes with exercise testing. Diagnostic value and hemodynamic implications.
abstract: To evaluate the diagnostic potential and hemodynamic significance of exercise-induced multiple-lead QRS changes, we studied exercise test responses in 230 patients with chest pain syndromes undergoing Bruce protocol exercise tests. When increases in the R waves of multiple ECG leads (epsilon R) plus ST segment change greater than 1 mm were present, 74 of 75 patients (99%) had coronary disease; this was a higher percentage than that achieved with either measurement alone or when ST change was combined with increase in R in a single lead. Sixty-four of the 75 patients (85%) had multivessel disease, the most severe form of coronary artery disease. Left ventricular end-diastolic pressure (both at rest and after left ventriculography), presence and degree of resting ventricular asynergy, and ejection fraction were all significantly more abnormal in patients whose epsilon R increased, regardless of ST-segment change. Further, in patients who stopped exercise because of cardiac symptoms, exercise duration and the product of heart rate times blood pressure were significantly lower when epsilon R increased. Thus, the mechanism for the increase in epsilon R with exercise in patients with coronary artery disease appears to be related to abnormalities in left ventricular function.
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis; D004562:Electrocardiography; D005080:Exercise Test; D005189:False Positive Reactions; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000627:therapeutic use; D012129:Respiratory Function Tests
chemical_list: D011433:Propranolol