Features of the electrocardiogram in TMEM43 p.S358L arrhythmogenic cardiomyopathy

Background

The electrocardiogram (ECG) is important in the diagnostic evaluation of arrhythmogenic cardiomyopathy (ACM).

Objective

The purpose of this study was to identify ECG features associated with TMEM43 p.S358L ACM during long-term assessment.

Methods

A total of 634 ECGs were collected from a retrospective cohort of 68 patients with TMEM43 p.S358L ACM. Abnormalities in repolarization, depolarization, conduction intervals, QRS voltage, and rhythm were analyzed.

Results

Sixty-eight patients (32 male, 36 female) with ≥5 ECGs (median, 9; range, 5–17) during 20.5 ± 8.0 years were included. During follow-up, 56 of 68 (82.4%) had an abnormality. Task Force criteria repolarization abnormalities were rare. Terminal activation duration ≥55 ms was common (20/32 male patients [62.5%]; 13/36 female patients [36.1%]). An epsilon wave was demonstrated in 2 female patients. Significant prolongation in the QRS duration occurred for male patients (97.3 ± 11.6 ms to 137.6 ± 24.8 ms; P < .001) and female patients (90.4 ± 12.1 ms to 117.4 ± 24.0 ms; P < .001). The most common finding was R wave <3 mm in V₃ (poor R-wave progression). Loss of the R wave in V₃ <3 mm followed by development of an intraventricular conduction delay or complete left bundle branch block was seen in most patients (42/68 [61.8%]), occurring earlier in male than in female patients (P < .02).

Conclusion

Repolarization Task Force criteria and epsilon waves are rare in TMEM43 p.S358L ACM. The ECG in TMEM43 p.S358L ACM is characterized by loss of the R wave in V₃ to <3 mm and QRS prolongation with development of an intraventricular conduction delay or left bundle branch block.