Manual-based versus automation-based measurements of the amplitude of QRS complexes and T waves in patients with changing edematous states: clinical implications

Most of the previous work pertaining to the impact of peripheral edema on the ECG has been based on manual measurements. Comparison of manual- and automation-based measurements of P waves has been previously carried out. The objective of this study was to compare manual and automated measurements of QRS complexes and T waves. The sum of the amplitude of QRS complexes for manual (ΣQRSm) and automated (ΣQRSa) and for T waves for manual (ΣTm) and automated (ΣTa) measured in the 12-leads of the ECGs was calculated in 28 patients with peripheral edema and 28 controls, without change in their weight during hospitalization; data points (n = 125) from all phases of the study were lamped together. ΣQRSm was 114.1 ± 46.2, and ΣQRSa was 125.4 ± 49.5 (n = 125); correlation of ΣQRSm and ΣQRSa was excellent (r = 0.98, P = .00005). ΣTm was 18.1 ± 13.3, and ΣTa was 19.8 ± 12.7 (n = 125); correlation of ΣTm and ΣTa was excellent (r = 0.96, P = .00005). Correlations of ΣQRSm and ΣTm (r = 0.43, P = .0002), as well as ΣQRSa and ΣTa (r = 0.49, P = .00005) were fair to moderately good, correspondingly. Manual and automated measurements of the sums of the amplitudes of the QRS complexes and T waves are well correlated and differ by approximately 9%, with the manual measurements generating lower values. Automated measurements of the QRS complexes and T waves are reliable and can be used in the diagnosis and monitoring of patients showing changes in the amplitude of these 2 components of the ECG curve.