Short-term repeatability of electrocardiographic criteria of left ventricular hypertrophy

Background Left ventricular hypertrophy (LVH) is a marker of cardiac end-organ damage and a risk factor for cardiovascular morbidity and mortality. Although clinical trials and cohort studies commonly use the electrocardiogram (ECG) for LVH assessment, the repeatability of ECG-LVH criteria has not been sufficiently examined. Therefore, we evaluated the repeatability of ECG-LVH criteria. Methods Participants (n = 63) underwent two standard ECGs at each of two visits, two weeks apart. The ECGs were processed centrally to calculate Cornell voltage (CV) LVH, Cornell voltage product (CVP) LVH, Sokolow-Lyon (SL) LVH, and Sokolow-Lyon product (SLP) LVH. We also used the waveforms measurements contributing to these LVH criteria as continuous variables, referred to here as CV-index, CVP-index, and SL-index. We calculated the intraclass correlation coefficient (ICC), minimal detectable change (95% confidence), and the prevalence-adjusted bias-adjusted kappa (PABAK). Results ICCs (95% confidence intervals (CI)) were 0.97 (0.96, 0.98) for CV-index, 0.97 (0.95, 0.98) for CVP-index, and 0.93 (0.90, 0.96) for log of SL-index. Minimal detectable change between repeat measures of CV-index, CVP-index, and log of SL-index were >= 236.7 mV, >= 26.7 mV, and >= 0.09 mV, respectively. The within-visit PABAK was 1 for all ECG-LVH criteria, except for the first visit SLP-LVH (PABAK = 0.93). Between-visit PABAK ranged from 0.83 to 0.97 across LVH criteria. Conclusions CV, CVP, and SL ECG-LVH as continuous variables have excellent repeatability, and as binary variables have excellent within-visit agreement and good between-visit agreement. These results alleviate concerns about the repeatability the ECG-LVH use in clinical trials and epidemiologic studies.