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 (SigmaQRSm) and automated (SigmaQRSa) and for T waves for manual (SigmaTm) and automated (SigmaTa) 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. SigmaQRSm was 114.1 +/- 46.2, and SigmaQRSa was 125.4 +/- 49.5 (n = 125); correlation of SigmaQRSm and SigmaQRSa was excellent (r = 0.98, P = .00005). SigmaTm was 18.1 +/- 13.3, and SigmaTa was 19.8 +/- 12.7 (n = 125); correlation of SigmaTm and SigmaTa was excellent (r = 0.96, P = .00005). Correlations of SigmaQRSm and SigmaTm (r = 0.43, P = .0002), as well as SigmaQRSa and SigmaTa (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.