Heart rate adjustment of ST-segment depression for reduction of false positive electrocardiographic responses to exercise in asymptomatic men screened for coronary artery disease.
Academic Article
Overview
abstract
The ability of heart rate (HR) correction of exercise-induced ST-segment depression (the delta ST/HR index) to reduce the number of false positive exercise electrocardiograms during initial screening for occult coronary artery disease (CAD) was examined in active, asymptomatic men from the Army Reserve. Among 606 consecutive men given treadmill tests, 62 asymptomatic subjects with normal results on resting electrocardiograms but abnormal outcomes on standard exercise electrocardiograms underwent rest and exercise radionuclide cineangiography, and the 10 subjects with abnormal radionuclide findings then underwent coronary angiography. A previously established delta ST/HR index less than 1.6 microV/beat/min correctly identified 34 of 52 subjects (65%) who, despite abnormal standard exercise electrocardiographic findings, had no rest or exercise radionuclide abnormalities. A delta ST/HR index greater than or equal to 1.6 microV/beta/min detected 7 of 7 subjects with abnormal radionuclide cineangiograms who had CAD at cardiac catheterization, but also identified 2 of 3 subjects with an abnormal radionuclide test who had no CAD. In contrast to the 7 of 62 subjects (11%) with abnormal standard exercise test criteria who had radionuclide and angiographic evidence of CAD, a delta ST/HR index partition of 1.6 microV/beat/min separated subjects into subgroups with 0% (0 of 35) vs 26% (7 of 27) prevalences of CAD by serial diagnostic evaluation (p less than 0.01). Thus, among asymptomatic subjects with abnormal electrocardiographic responses to exercise, simple HR correction of the magnitude of ST-segment depression reduced by 56% the number of subjects with standard exercise test criteria leading to referral for additional diagnostic evaluation, without loss of sensitivity for angiographically proven CAD and with accurate negative predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)
