Incremental value of high-frequency QRS analysis for diagnosis and prognosis in suspected exercise-induced myocardial ischaemia

Abstract

Aim: Exercise stress testing is used to detect myocardial ischaemia, but is limited by low sensitivity and specificity. The authors investigated the value of the analysis of high-frequency QRS components as a marker of abnormal depolarization in addition to standard ST-deviations as a marker of abnormal repolarization to improve the diagnostic accuracy. Methods and results: Consecutive patients undergoing bicycle exercise stress nuclear myocardial perfusion imaging were prospectively enrolled. Presence of myocardial ischaemia, the primary diagnostic endpoint, was adjudicated using MPI and coronary angiography. Automated high-frequency QRS analysis was performed in a blinded fashion. The prognostic endpoint was major adverse cardiac events (MACEs) during two years of follow-up. Exercise-induced ischaemia was detected in 147/662 patients (22%). The sensitivity of high-frequency QRS was similar to ST-deviations (46% vs. 43%, p=0.59), while the specificity was lower (75% vs. 87%, p<0.001). The combined use of high-frequency QRS and ST-deviations classified 59% of patients as 'rule-out' (both negative), 9% as 'rule-in' (both positive) and 32% in an intermediate zone (one test positive). The sensitivity for 'rule-out' and the specificity for 'rule-in' improved to 63% and 97% compared with ST-deviation analysis alone (both p<0.001). MACE-free survival was 90%, 80% and 42% in patients in the 'rule-out', intermediate and 'rule-in' groups (p<0.001). After adjustment for age, gender, ST-deviations and clinical post-test probability of ischaemia, high-frequency QRS remained an independent predictor for the occurrence of MACEs. Conclusion: The use of high-frequency QRS analysis in addition to ST-deviation analysis improves the diagnostic accuracy during exercise stress testing and adds independent prognostic information.

The combination of high‐frequency QRS and ST‐segment alterations during exercise stress tests enhanced the diagnostic efficacy for coronary artery disease

“…Therefore, compared with the serial test, the parallel test may have greater clinical value. This finding aligns with results from a large‐scale study led by Professor Schaerli et al, 15 where they employed a combined algorithm. This algorithm categorized patients as “rule‐out” (both tests negative), “rule‐in” (both tests positive), and an intermediate zone (only one test positive).…”

“…Investigations involving human subjects have evidenced the superiority of HF‐QRS analysis over conventional ST‐segment analysis 13,14 . Integration of these two methodologies enhances diagnostic accuracy for myocardial ischemia 15 . In these research endeavors, MPI served as the benchmark for ischemia, providing a physiological representation of CAD.…”

“… 13 , 14 Integration of these two methodologies enhances diagnostic accuracy for myocardial ischemia. 15 In these research endeavors, MPI served as the benchmark for ischemia, providing a physiological representation of CAD. Nonetheless, its correlation with anatomical CAD, as identified by coronary angiography (CAG), is not very satisfactory.…”

Diagnostic and prognostic value of ST-segment deviation scores in suspected acute myocardial infarction

“…Obviously, providing diagnostic value in the ED is even more important than providing prognostic value in patients with established disease (NSTEMI). 5,8,11,13,30–34…”

Enhancing the diagnosis of functionally relevant coronary artery disease with machine learning

“…Resting heart rate, blood pressure, and 12-lead resting ECG were recorded before exercise. A standardised, stepwise, and symptom-limited upright bicycle exercise test was performed 54 , 55 . Beta-blockers and antianginal medication were paused for at least 48 h and nitrates for at least 24 h before testing.…”