This study compared thallium stress testing and exercise changes in QRS duration using a computerized ‘optic scanner’ in three groups. Group 1 consisted of 108 subjects with positive exercise ECG tests by ST-T segment criteria and with proven coronary artery disease. Group 2 included 19 subjects with nondiagnostic exercise ECG ST-T changes and with proven coronary artery disease. Group 3 was formed by 38 healthy controls. Group 1: Mean increase in exercise QRS width of 12.4 ± 14 ms. Group 3: Mean decrease in exercise QRS width of 4.9 ± 9.3 ms(p < 0.0001). Group 2: Mean QRS prolongation of 7.8 ± 9.2 ms, which was significantly different from the controls (p < 0.0001) but not from group 1. When compared to thallium stress testing, exercise QRS prolongation had a sensitivity of 93%, specificity of 71%, relative risk of 5, and positive predictive value of 86%. QRS duration measurement can improve the diagnostic accuracy of the exercise ECG stress test.

The purpose of this study is to measure QRS duration changes in the human model of ischemia during percutaneous transluminal coronary angioplasty (PTCA) and compare these results to the commonly used ischemia markers, chest pain, and classical ST‐T changes. Using a computerized method, QRS duration was measured in 51 patients undergoing elective PTCA. Three milliseconds (msec) or more prolongation of the QRS at peak inflation was considered to be an ischemic response. The results were compared to chest pain and ST‐T changes and were analyzed for inflation site within individual coronary arteries. Forty‐two patients had a pathological prolongation of the QRS during PTCA. Thirty‐two patients developed chest pain, while 19 had ischemic ST‐T changes. QRS duration was more prolonged in PTCA to proximal or middle segments of major arteries or their large branches, while it was less prolonged in distal segments or smaller branches. Using our method, QRS prolongation was an ischemia marker in most patients during PTCA and was more sensitive than chest pain or ST‐T changes. QRS duration was more prolonged with occlusion of proximal and middle segments of major arteries. Cathet. Cardiovasc. Intervent. 50:177–183, 2000. © 2000 Wiley‐Liss, Inc.

Noncardiac factors were better predictors of the effort tolerance of patients with coronary artery disease than parameters of left ventricular function at entry to an exercise program or after 6 months of training. A similar degree of adaptation to training was seen in all patients regardless of their degree of left ventricular systolic or diastolic dysfunction.