Incidence and Predictors of Cardiac Implantable Electronic Devices Malfunction with Radiotherapy Treatment.

Aims: To investigate the incidence of cardiac implantable electronic devices (CIED) malfunction with radiotherapy (RT) treatment and assess predictors of CIED malfunction.

Methods: A 6-year retrospective analysis of patients who underwent RT with CIED identified through the radiation oncology electronic database. Clinical, RT (cumulative dose, dose per fraction, beam energy, beam energy dose, and anatomical area of RT) and CIED details (type, manufacturer, and device malfunction) were collected from electronic medical records.

Results: We identified 441 patients with CIED who underwent RT. CIED encountered a permanent pacemaker (PPM) (78%), cardiac resynchronization therapy-pacing (CRT-P) (2%), an implantable cardioverter defibrillator (ICD) (10%), and a CRT-defibrillator (CRT-D) (10%). The mean cumulative dose of RT was 36 gray (Gy) (IQR 1.8-80 Gy) and the most common beam energy used was photon ≥10 megavolt (MV) with a median dose of 7 MV (IQR 5-18 MV). We further identified 17 patients who had CIED malfunction with RT. This group had a higher cumulative RT dose of 42.5 Gy (20-77 Gy) and a photon dose of 14 MV (12-18 MV). None of the malfunctions resulted in clinical symptoms. Using logistic regression, the predictors of CIED malfunction were photon beam energy use ≥10 MV (OR 5.73; 95% CI, 1.58-10.76), anatomical location of RT above the diaphragm (OR 5.2, 95% CI, 1.82-15.2), and having a CIED from the ICD group (OR 4.6, 95% CI, 0.75-10.2).

Conclusion: Clinicians should be aware of predictors of CIED malfunction with RT to ensure the safety of patients.