Improved efficiency of treadmill exercise testing using a multiple lead ECG system and basic hemodynamic exercise response.
One hundred consecutive men with a normal ECG at rest had a maximal treadmill test using 14 leads during and post-exercise. Coronary arteriography performed the following day revealed coronary stenoses greater than or equal to 70% in 66 patients. Test results obtained from a V5 lead were compared to different lead combinations and were correlated with arteriographic findings. A positive exercise test occurred in 37 men using an isolated V5 lead compared to 50 men (P less than 0.05) using 11 leads, 52 men (P less than 0.05) using a combined CM5, CC5, Cl (inferior) lead system and 58 (P less than 0.001) men using all 14 leads. The predictive value of a positive test varied between 89-95% and was not changed significantly by the addition of multiple leads. The 14 lead ECG was positive in 43/45 (96%) patients with multivessel disease. Parameters which helped to predict multivessel disease using 14 leads were 1) the time that ischemia first appeared 2) the pressure-rate product at the time ischemia first appeared, and 3) the maximum workload that could be attained. In general, the magnitude of ST-segment depression and the time required for a positive ECG to return to normal postexercise were not useful predictors of multivessel disease. We conclude that the use of multiple leads improves the sensitivity and efficiency of the maximal treadmill exercise test. The usefulness of exercise test results can be further improved if multiple leads are combined with physiologic data collected during exercise.
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