Signal averaged ECG in patients with early repolarization

Abstract

Background Early repolarization (ER) pattern is diagnosed when the J‐point is elevated on the patient's electrocardiogram. The aim of this study was to evaluate signal‐averaged electrocardiography (SAECG) in patients with ER pattern. Methods Subjects were divided into three groups: 1‐patients with normal ECG pattern (control group); 2‐patients with J‐point elevation in the inferior leads; and 3‐patients with J‐point elevation in non‐inferior leads. Results The mean filtered QRS duration in groups with J‐point elevation in inferior leads and non‐inferior leads and in the control, was 86.4 ± 23.4 msec, 84.8 ± 26.6 msec, and 85.8 ± 24.8 msec, respectively, indicating no significant difference across the three groups. The mean duration of terminal QRS < 40µV was 21.2 ± 4.2 msec, 22.8 ± 4.6 msec, and 23.1 ± 4.5 msec in the mentioned groups, respectively, without a significant difference between the groups. Additionally, the mean root‐mean‐square voltage of terminal 40 msec was 34.5 ± 8.3 µV, 35.3 ± 8.6µV, and 35.7 ± 9.2 µV in patients with increased J‐point in inferior leads, non‐inferior leads, and the control group, respectively, showing no difference between the groups. Conclusion In conclusion, we found that parameters in SAECG did not have any significant difference between patients with ER pattern and healthy individuals. Moreover, we concluded that SAECG cannot distinguish the patients with elevated J‐point in inferior leads from non‐inferior leads. Overall, SAECG does not appear to be a reliable diagnostic tool for the assessment of ER pattern.

Non-Contact Heart Sound Measurement Using Independent Component Analysis

“…Therefore, the quasi-periodicity of the heart sound and the ECG were utilized. The minute potential changes in the ECG can be detected by [25] synchronously averaging it based on its R waves (referred to as R henceforth) to attenuate asynchronous noises. R is the strongest component of the ECG caused by myocardial excitement and is generally used for heart rate detection.…”