Snyder Michelle L, Soliman Elsayed Z, Whitsel Eric A, Gellert Kapuaola S, Heiss Gerardo
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Epidemiological Cardiology Research Center (EPICARE), Division of Public Health Sciences Wake Forest School of Medicine, Division of Public Health Sciences, Winston Salem, NC, USA.
J Electrocardiol. 2014 Mar-Apr;47(2):257-63. doi: 10.1016/j.jelectrocard.2013.11.007. Epub 2013 Nov 25.
P wave indices and PR interval from 12-lead electrocardiograms (ECGs) are predictors of cardiovascular morbidity and mortality, but their repeatability has not been examined.
Determine the short-term repeatability of P wave indices (P axis, maximum P area and duration, P dispersion and P terminal force in V1) and PR interval.
Participants (n=63) underwent two standard ECGs at each of two visits, two weeks apart. We calculated the intra-class correlation coefficient (ICC), weighted kappa, and minimal detectable change and difference.
ICCs were 0.93 for PR interval, 0.78 for P axis, 0.77 for maximum P area, and 0.58 for maximum P duration. Within- and between-visit Kappa were 0.30 and 0.11 for P dispersion, and 0.68 and 0.46 for P terminal force.
Repeatability of PR duration was excellent, that of P wave axis and maximum area was fair, and maximum P wave duration and terminal force was poor. Repeatability of P wave dispersion was fair within visit, yet poor between visits. These results illustrate potential biases when measurement error of some P wave indices is ignored in clinical and epidemiologic studies.
12导联心电图（ECG）的P波指标和PR间期是心血管疾病发病率和死亡率的预测指标，但其重复性尚未得到研究。
确定P波指标（P轴、最大P波面积和时限、P波离散度以及V1导联的P波终末电势）和PR间期的短期重复性。
63名参与者在两次相隔两周的就诊时分别接受了两次标准心电图检查。我们计算了组内相关系数（ICC）、加权kappa系数以及最小可检测变化和差异。
PR间期的ICC为0.93，P轴为0.78，最大P波面积为0.77，最大P波时限为0.58。P波离散度的就诊内和就诊间kappa系数分别为0.30和0.11，P波终末电势的分别为0.68和0.46。
PR间期的重复性极佳，P波轴和最大面积的重复性尚可，最大P波时限和终末电势的重复性较差。P波离散度的重复性在就诊内尚可，但在就诊间较差。这些结果表明，在临床和流行病学研究中，若忽略某些P波指标的测量误差，可能会产生偏差。
