Validation of CalECG software for primary prevention heart failure patients: Reducing inter-observer measurement variability

Abstract

In primary prevention heart failure patients the 12‑lead electrocardiogram (ECG) may be useful for the prediction of ventricular arrhythmias. However, inter-observer measurement variability first needs to be identified and any software used, validated. To compare manual ECG measures with CalECG software and to assess the reliability of visual recognition of fragmented QRS (fQRS) by advanced cardiology trainees. 30 pre-implant ECGs were assessed on patients who met guidelines for primary prevention Implantable Cardiac Defibrillator. Parameters included RR, PR, QT, QRS duration, axis location, fQRS and T wave peak to T wave end (TpTe). ECGs were analyzed by members of the cardiology department with different levels of experience, and compared to CalECG software. Interobserver agreement was assessed using Fleiss' Kappa (κ) and intraclass correlation coefficients (ICC). Pearson correlation coefficient (r) was used to compare human and software measures. Strong/very strong correlation was recorded across manual ECG measures (ICC = 0.749-0.979, p ≤ 0.0001) with moderate/strong correlation for TpTe (ICC = 0.547-0.765, p ≤ 0.001). Advanced cardiology trainees demonstrated substantial agreement on ECG interpretation (κ = 0.788, p ≤ 0.0001), however, reliability of fQRS assessment was only moderate for identification (κ = 0.5, p ≤ 0.0001) and fair for location (κ = 0.295, p = 0.001). CalECG software showed strong/very strong correlation with manual measurement for standard measures (r = 0.756-0.977, p ≤ 0.001). Concordance between human and software TpTe measurements varied between leads, with V5 showing a non-significant weak correlation (r = 0.197). CalECG software showed strong/very strong correlation with standard manual measures which affirms its use in ECG analysis. Advanced cardiology trainees showed greater variability in the identification and location of fQRS.