Comparative sensitivity and specificity of exercise electrocardiographic lead systems.

A comparison of current exercise electrocardiographic lead systems reveals differences in the sensitivity and specificity of S-T segment shifts diagnostic of obstructive coronary artery disease. The differences are explained in part by differences in population samples, lead systems and criteria for positivity. Multiple electrocardiographic lead recording in symptomatic patients during and after exercise improves sensitivity in detecting S-T segment shifts with only a small decrease in specificity. A review of population screening studies in asymptomatic subjects shows a wide selection of different exercise electrocardiographic lead systems and criteria for a positive test. Few screening studies have compared the prevalence of different S-T segment configurations in individual leads of a simultaneously recorded multiple lead system during or after exercise. Data from animal studies of myocardial ischemia suggest why 100 percent sensitivity in detecting obstructive coronary disease is unlikely to be obtained with surface electrocardiographic recordings. Additional research is required to identify the optimal set of diagnostic exercise electrocardiographic leads and criteria for positivity so that maximal predictive accuracy can be obtained for different patient subsets.