high-frequency qrs analysis to supplement st evaluation in exercise stress electrocardiography: incremental diagnostic accuracy and net reclassification

Exercise stress electrocardiography (ecg) alone is underutilized in part due to poor diagnostic accuracy. high-frequency qrs analysis (hf-qrs) is a novel tool to supplement st evaluation during stress ecg. we compared the diagnostic accuracy and net reclassification of hf-qrs analysis compared with st evaluation for substantial myocardial ischemia by exercise spect myocardial perfusion imaging (mpi). exercise spect mpi was performed in 257 consecutive eligible patients (mean age 59 ± 12, 67% male). an ischemic hf-qrs pattern was defined as a ≥ 1 µv absolute reduction and a ≥ 50% relative reduction of the root-mean-square of the 150-250 hz band signal in ≥ 3 leads. left ventricular ischemia of ≥ 10% on spect mpi was the diagnostic standard for substantial myocardial ischemia. hf-qrs analysis demonstrated incremental diagnostic value to st evaluation plus clinical risk factors (auc 0.804 vs 0.749, p < .0001). a hf-qrs + st -analysis strategy identified 92.3% of subjects with substantial ischemia and no abnormality in 59.9% of the cohort. no cardiac events occurred in patients without substantial ischemia identified by hf-qrs analysis. in this prospective analysis, exercise stress ecg with hf-qrs analysis identified any and substantial ischemia with high diagnostic accuracy and allow more than half of referred patients to safely avoid imaging.