Wearable cardioverter-defibrillator as a bridge to cardiac transplantation: A national database analysis.

Background: Life-threatening ventricular arrhythmias (VAs) and sudden cardiac death (SCD) are common in patients awaiting heart transplantation (HT), and the implantable cardioverter-defibrillator (ICD) is often used for primary prevention in this setting. Use of ICDs in these patients is not without risks and is sometimes contraindicated. The wearable cardioverter-defibrillator (WCD) may be a reasonable alternative to bridge the period of risk leading up to HT.

Methods: We obtained a convenience sample of patients prescribed an WCD as a bridge therapy to HT. The available data consisted of demographics, cardiac transplantation status, associated comorbidities, device use, device-stored electrocardiogram (ECG) and reason for discontinuing the WCD. Statistical analyses were performed using SPSS version 17 and GraphPad PRISM 5.

Results: The registry included 121 patients consisting of 83 (69%) men and 38 (31%) women. The mean age was 44 ± 18 years. Mean ejection fraction was 25 ± 15%. Non-ischemic cardiomyopathy (CMP) was the underlying diagnosis in 67 (55%) patients, whereas 21 (17%) patients had ischemic CMP and 33 (27%) had a mixed or uncharacterized CMP. New York Heart Association Class III heart failure was present in 32% and 34% were in Class IV. Eighty-eight patients (73%) were being evaluated for HT or were on an HT waiting list, and 33 patients (27%) had had a prior HT, experienced rejection, and were awaiting re-transplantation. The patients wore the WCD for an average of 127 ± 392 days (median 39 days) with average daily use of 17 ± 7 hours (median 20 hours). Seven patients (6%) received appropriate WCD shocks. Fifty-one patients (42%) ended use after ICD implantation and 13 patients (11%) after HT. There were 11 deaths (9%).

Conclusions: A significant proportion of patients on the HT waiting list will have VA. WCD use in our study showed high compliance and efficacy and a low complication rate, suggesting that the WCD is a reasonable bridge therapy for preventing SCD in patients awaiting HT.