Reader‐ and Instrument‐Dependent Variability in the Electrocardiographic Assessment of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland, USA
Journal of Cardiovascular Electrophysiology (Impact Factor: 2.88). 11/2010; 22(5):561 - 568. DOI: 10.1111/j.1540-8167.2010.01961.x

ABSTRACT Variability in ECG Assessment in ARVD/C. Introduction: Despite the use of standardized definitions, widely varying prevalence estimates of electrocardiographic (ECG) features related to arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) have been reported in different cohorts. This study was aimed at examining the variability in the ECG interpretation resulting from the same reader, different readers, and using different ECG-resolutions.Methods and Results: Blinded to other clinical data, 2 readers examined quantitative and qualitative ECG features of 20 (10 ARVD/C) randomly selected individuals. ECGs were recorded at standard-speed (SS) and double-speed-double-amplitude (DS) settings. The SS ECGs were scanned, magnified 4×, and evaluated using electronic calipers (EL). One reader repeated all measurements. For both readers, the intraclass correlation coefficient (ICC) for the measurement of QRS duration was good between conventional and electronic evaluation [DS vs EL: Reader 1—0.64 (0.52–0.73); Reader 2—0.67 (0.55–0.76)][SS vs EL: Reader 1—0.60 (0.47–0.70); Reader 2—0.60 (0.47–0.70)]. Using the same resolution, the intrareader ICC was good for SS [0.70 (0.59–0.78)], DS [0.85 (0.80–0.90)], and EL [0.70 (0.69–0.83)] resolutions, but deteriorated for interreader comparisons [0.50 (0.36–0.62), 0.75 (0.66–0.82), and 0.75 (0.66–0.82), respectively]. For qualitative parameters, the intra- and interreader agreement was inconsistent for all but 2 parameters. Both readers were in perfect agreement while interpreting right precordial T-wave inversion [κ= 1] and right bundle branch block morphology (RBBB) [κ= 0.83 (0.5–1.0)] even when using SS resolution.Conclusions: Right precordial t-wave inversion and RBBB are the only ECG parameters that can be detected consistently even using the conventionally used ECG-resolution. The substantial variability in evaluation of other parameters is not improved even with the use of higher resolutions. (J Cardiovasc Electrophysiol, Vol. 22, pp. 561-568 May 2011)

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    ABSTRACT: Background: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by delay in depolarization of the right ventricle, detected by prolonged terminal activation duration (TAD) in V1-V3. However, manual ECG measurements have shown moderate-to-low intra- and inter-reader agreement. The goal of this study was to assess reproducibility of automated ECG measurements in the right precordial leads. Methods: Pairs of ECGs recorded in the same day from Johns Hopkins ARVD/C Registry participants In = 247, mean age 35.2 +/- 15.6 years, 58% men, 92% whites, 11(4.5%) with definite ARVD/C] were retrospectively analyzed. QRS duration, intrinsicoid deflection, TAD, and T-wave amplitude in the right precordial leads, as well as averaged across all leads QRS duration, QRS axis, Taxis, QTc interval, and heart rate was measured automatically, using 12SL TM algorithm (GE Healthcare, Wauwatosa, WI, USA). Intrin-sicoid deflection was measured as the time from QRS complex onset to the alignment point of the QRS complex. TAD was calculated as the difference between QRS duration and intrinsicoid in V1-V3. Reproducibility was quantified by Bland-Altman analysis (bias with 95% limits of agreement), Lin's concordance coefficient, and Bradley-Blackwood procedure. Results: Bland-Altman analysis revealed satisfactory reproducibility of tested parameters. V1 QRS duration bias was -0.10 ms [95% limits of agreement -12.77 to 12.56 ms], V2 QRS duration bias -0.09 ms [-11.13 to 10.96 ms]; V1 TAD bias 0.14 ms [-13.23 to 13.51 ms], V2 TAD bias 0.008 ms [-12.42 to 12.44 ms]. Conclusion: Comprehensive statistical evaluation of reproducibility of automated ECG measurements is important for appropriate interpretation of ECG. Automated ECG measurements are reproducible to within 25%.
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