ECG Anomalies of the Transplanted Heart—What Do They Tell?

Background: Heart transplantation (HTX) is a viable treatment option for terminal heart failure in pediatric patients. Postoperative diagnostic evaluations and follow-up protocols include electrocardiograms (ECG), which may show differences compared with the healthy population. The aim of this study was to analyze the rhythm profile of pediatric patients post-HTX at the Pediatric Heart Center Vienna. An emphasis was put on allograft rejections.

Methods: From pediatric patients transplanted between 2000 and 2020, ECG parameters have been investigated retrospectively. Up to five follow-up examinations were documented in each patient. Subgroup analysis was conducted according to biopsy results during the control period. Furthermore, from 2020 to 2021, long-term ECG and clinical data was collected prospectively.

Results: In total, 56 patients were included in this study. 136 ECG, 28 long-term ECG and 78 biopsies were available for analysis. Transplant rejections were observed in 22 (two times as Grade 2 R, once as Grade 3 R; according to the International Society for Heart and Lung Transplantation standardized cardiac biopsy grading for acute cellular rejection) biopsy results. Sinus rhythm was dominant in 99.26% of all ECGs and in 96.43% of all long-term ECGs, with atrioventricular (AV)-block I° being present in 14.71%. AV-block II and preexcitation were incidental. PR-shortening and PR- prolongations were recorded in 17.04% and 18.52%. P-pulmonale was observed in 6.45% of cases. 48.89% of ECGs showed normal QRS axis. QRS-shortening and -prolongation occurred in 30.15% and 4.41%. Incomplete right bundle branch block (RBBB) was common with 66.91% of cases, with complete RBBB being recorded in 1.47%. Further, 9.38% of the patients showed pathological Q-waves, ST-elevations and ST-depressions were both seen once. QTc- prolongations were found in 8.33% of ECGs. Inverted T-waves were recorded in 87.40%. Elevated heart rates were found in 33.82% of all ECGs and 25.00% of all long-term ECGs. Overall, decreased heart rate variability was observed. Supraventricular and ventricular extra beats were present in 39.29% and 40.74%, respectively.

Conclusion: Although ECG changes after pediatric heart transplantation were common, only a few indicate an ongoing transplant rejection. Our observations may serve as a basis for future studies to assess the value of ECG for functional behavior and rejection of the transplanted heart in pediatric HTX recipients.

Publication History

Article published online:
13 February 2024