Background: Noninvasive cardiac radioablation has been used in patients with treatment refractory VT. Late effects of radiation are expected, but the timing, severity, and management of these adverse events (AE) are unknown.
Objective: Report management strategies of AEs after cardiac radioablation.
Methods: 19 patients received a single 25 Gray fraction to a discrete ventricular target on the ENCORE-VT prospective trial and were regularly screened for AE per protocol.
Results: Median follow up was 26.8 months. In the first 90 days, the most common AEs were mild: fatigue (n=12), dyspepsia (6) and heart failure (5). After 3 months, the most common treatment-related high-grade AE was heart failure (13), which responded to diuresis, but 2 patients had VT storm when initiated on dobutamine. Late asymptomatic pericardial effusions (3) were found on CT scans. Diagnostic pericardiocenteses demonstrated bland, transudative effusions, managed with oral colchicine. Radiation pneumonitis was commonly observed on CT scans in, but rarely symptomatic. When symptomatic (2), oral steroid therapy was rapidly effective. One patient experienced ventricular fibrillation related to iatrogenic acquired long-QT from repeated antibiotic use for radiation pneumonitis. A single patient developed a gastropericardial fistula which required surgical repair. There have been no AEs with regards to ICD malfunction, new heart block, or acute coronary syndromes.
Conclusion: Lessons learned from rigorous clinical follow-up of patients who have received noninvasive cardiac radioablation are defining how future patients should be screened and treated.