Evaluation of Electrocardiographic Changes after Arterial Switch Operation

BACKGROUND Transposition of Great Arteries (TGA) is a serious congenital heart disease which can be accompanied by good outcomes with anatomic correction within the first few weeks of life. OBJECTIVES The present study aimed to evaluate electrocardiographic changes in the children with uncomplicated Arterial Switch Operation (ASO). PATIENTS AND METHODS Twelve lead electrocardiograms were obtained from thirty-three patients with TGA after ASO. Then, the patients' QT-dispersion and P-wave dispersion were compared to those of 33 age- and gender-matched individuals as the normal control group. Both groups were also evaluated by M-mode echocardiography. Student's t-test and Pearson correlation were used to analyze the data. Besides, P < 0.05 was considered as statistically significant. RESULTS The mean age of the patients and the control group was 41 ± 3.7 and 40.12 ± 4.2 months, respectively. Comparison of P wave, T wave, QRS complex, PR interval, QT segment, and corrected QT segment showed significant differences in the frequency of inverted T wave in pericardial leads [V3, V4, V5, and V6] (P = 0.004; more in patients), P wave amplitude in lead II (P < 0.001; more in patients), R wave amplitude in V1 (P = 0.016; smaller in patients), R and S waves amplitude in V6 (P = 0.004 and P = 0.001; taller in patients), corrected QT segment (in lead V5; P < 0.0001: prolonger in patients), and PR interval (P = 0.001; prolonger in patients). However, no significant differences were found regarding the vector axis and heart rate. Right bundle branch block (18% vs. 0%), Bifascicular (3% vs. 0%), and first-degree blocks (15% vs. 0%) were significantly more in the patients. Besides, the PR interval was longer in the corrected complex TGA (146 ± 24.4 vs. 127.7 ± 23.1, P = 0.001). Moreover, R/S ratio in lead V1 was significantly prolonger, among the patients (2.86 ± 3.35 vs. 0.706 ± 0.53, P = 0.002). Nonetheless, no significant was observed between the patients and controls concerning the mean of QT dispersion. On the other hand, the two groups were significantly difference in terms of P wave dispersion (25.7 ± 13.8 vs. 33.74 ± 12.9, P = 0.024). CONCLUSIONS In this study, first-degree block and right bundle branch were detected in the operated patients with TGA. Increased P dispersion in these patients may increase the risk of atrial arrhythmia. Thus, long-term follow-up is necessary in these patients.