Abstract 2296: QT Variability Predicts Sudden Cardiac Death Late After Heart Transplantation
Background: To better define cardiac transplant recipients at risk for sudden cardiac death (SCD) we analyzed the predictive value of QT variability (QTV) late after heart transplantion.
Methods: In a prospective study we enrolled 43 cardiac transplant recipients who underwent routine yearly surveillance coronary angiography to monitor for transplant coronary artery disease in the period from June 1st to September 1st, 2002. Patients less than 2 years out of transplant and those with recent (<1 month) evidence of rejection or infection were not included. At the time of angiography, we recorded a 5-minute high-resolution resting ECG and measured QT variability. QT variability was considered increased if above 75th percentile (High QTV group). Patients were followed for 3 years for SCD after ECG recording.
Results: High QTV was present in 11/43 (26%) of transplant recipients. High QTV group and the remaining cohort (Controls) did not differ with regards to age (53±9 years in High QTV group vs. 59±9 in Controls, P=0.25), gender (male: 73% vs. 81%, P=0.67), history of rejection incidence (1.18±1.08 vs. 0.76±0.70, P=0.12), or heart rate variability (SDNN: 12±4 ms vs. 11±4 ms, P=0.52; rMSSD: 34±5 ms vs. 30±6 ms; P=0.38). Transplant vasculopathy was more common in High QTV group (73%) than in Controls (38%, P=0.04). During follow-up 5 (12%) patients died of SCD. Patients with SCD displayed higher values of QT variability than survivors (SDNN: 8.3±2.6 ms vs. 3.4±2.2 ms, P=0.008; rMSSD: 11.1±2.1 ms vs. 4.3±2.2, P=0.003). High QT variability was an independent predictor of SCD in multivariate analysis (P=0.01).
Conclusions: High QT variability is related to transplant vasculopathy and predicts SCD late after heart transplantation.