Surface electrocardiography and histologic rejection following orthotopic heart transplantation

Background: Intraventricular conduction delay and QT interval dispersion may be related to electrical instability and the risk of ventricular arrhythmogenesis. The interlead variability of the QT interval on a surface 12-lead electrocardiogram (ECG) has been associated with an increased likelihood of sudden death in patients with long QT syndromes, in patients recovering from myocardial infarction, and dilated cardiomyopathy. We sought to determine the incidence of increased QT_C dispersion (QT_c-d) relative to biopsy grade of severity of rejection. Methods: Records of patients having undergone orthotopic heart transplantation (OHT) were reviewed focusing specifically on surface ECGs performed in temporal proximity to endomyocardial biopsy. Results: Seventy-five patients were evaluated on 1573 occasions, to include 999 surface ECGs, and 847 endomyocardial biopsies. There were 269 interpretable surface ECGs and endomyocardial biopsies performed within 1.1 ± 4.6 days. There were no identifiable trends in atrioventricular or intraventricular conduction abnormalities (to include right bundle branch block) when comparing those with and without significant rejection on endomyocardial biopsy. The mean QT_c-d of those with none (n = 34), mild (n = 194), moderate (n = 39), and severe (n = 2) rejection was 49 ± 29, 49 ± 35, 57 ± 38, 81 ± 7 ms, respectively (P = 0.28 by ANOVA of means). When comparing those with significant rejection so as to change management there was a trend toward increased dispersion (no to mild rejection, 49 ± 34 ms vs moderate to severe rejection, 59 ± 37 ms, P = 0.09). Conclusions: In this study investigating noninvasive ventricular depolarization/repolarization and correlation to histologic manifestation of rejection, there was suggestion, but no statistical significance, of QT _c-d and severity of rejection. QT_c-d should not be considered a sensitive marker for OHT rejection.