Early ventricular repolarization (J wave): association with other repolarization features.

Alexandru D. Corlan1, Milan B. Horacek2, Luigi De Ambroggi 3

1University Emergency Hospital - Bucharest - Romania,
2Dept. Physiology and Biophysics, Dalhousie University, Halifax, Canada
3IRCCS Policlinico San Donato, University of Milan - San Donato Milanese - Italy,

Proc. 35th Intl. Congr. Electrocardiology, St. Petersburg, p. 22

Archived by WebCite® at http://www.webcitation.org/67ivt2qpm Accessed: 2012-05-17. References added to this postprint, 2012-05-17.

Background

The presence on ECG recordings of an early repolarization (J) wave has been proposed [1-4] as a possible indicator of increased risk for malignant ventricular arrhythmias.

Purpose

To explore the association of the J wave with other indices based on repolarization and the contribution of early repolarization to other gender-related differences in indices based on the ST-T potentials, that were previously proposed as possible markers of arrhythmogenicity in certain subgroups and to exhibit gender differences.

Methods

We studied single cardiac cycle, body surface ECG recordings in healthy adults, 125 females and 134 males, previously recorded in the Department of Physiology and Biophysics, Dalhousie University. An investigator blinded to the gender and the values of any other repolarization indices examined standard ECG printouts in each recording and identified those with a J wave ( > 0.1mV in at least 2 leads). In each recording we separately calculated the similarity index SI1 (the ratio of the first eigenvalue from the principal component analysis of repolarization potentials [5,6]), the early repolarization deviation index ERDI (the average difference between 1 and the correlation of the instantaneous repolarization potential distribution at each instant before the peak of T and that at the peak of T) and the absolute correlation coefficients of the QRS integral maps with the first and second orthogonal components of repolarization (RT1 and RT2) [7]. Quantitative values are reported as mean ± standard deviation.

Results

A J wave was identified in standard leads in 10 females (95% confidence interval 4--14%) and 37 males (20--36%, p < 0.0001). J wave presence was separately associated with (1) a lower ERDI in females (0.15 ± 0.17 vs 0.30 ± 0.16, p<0.001) and in males (0.09 ± 0.08 vs 0.13 ± 0.10, p < 0.05)--thus females with a J wave had an ERDI in the same range with most males (2) a higher SI1 in females (0.78 ± 0.05 vs 0.72 ± 0.07, p < 0.01) but not in males (0.77 ± 0.06 vs 0.77 ± 0.05, p=NS); (3) a higher RT1 (0.78 ± 0.09 vs 0.54 ± 0.21, p < 0.001) and a lower RT2 (0.54 ± 0.10 vs 0.67 ± 0.20, p < 0.05) in females but non-significant differences in males (0.46 ± 0.24 vs 0.37 ± 0.23, p=NS) and (0.75 ± 0.19 vs 0.71 ± 0.21 p=NS).

Conclusions

The presence of the early repolarization in standard ECG leads was associated with significant differences in a variety of indices that describe repolarization, particularly in females. This phenomenon could explain in part the gender differences in similarity and deviation indices where the presence of the J wave is associated with a reduction of these differences in females.

References

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