Influence of radiotherapy on cardiac implantable devices and leads-a single-institution analysis and critical evaluation of current guidelines.

Purpose: Increasing life expectancy and advances in cancer treatment will lead to more patients needing both radiation therapy (RT) and cardiac implantable electronic devices (CIEDs). CIEDs, including pacemakers and defibrillators, are essential for managing cardiac arrhythmias and heart failure. Telemetric monitoring of CIEDs checks battery status, lead function, settings, and diagnostic data, thereby identifying software deviations or damage. This study evaluates the German Society for Radiation Oncology (DEGRO)/German Society for Cardiology (DGK) guideline, assessing real-world complications and risk factors and analyzing pacemaker and implantable cardioverter-defibrillator (ICD) lead function for their predictive value concerning device malfunction.

Methods: A total of 54 patients with pacemakers or ICDs who underwent radiation therapy were identified. Demographics, treatment courses, and device information from physical and digital records were extracted. DEGRO/DGK risk groups and pacemaker dependency at the start of RT were assessed. Delineation of the devices and lead insertion sites was performed in the treatment planning system. Dosimetric information from the treatment plans was then correlated with reports of standardized device checks.

Results: Over 80% of patients were treated with dual-chamber pacemakers or cardiac resynchronization therapy (CRT), and 16.7% had ICDs. One third of patients were pacemaker dependent. 59.3% of patients were in the low-risk category, 29.3% in the medium-risk, and 11.1% in the high-risk category. Thoracic irradiation resulted in the highest median dose to devices. Lead parameter deviations exceeding thresholds were found in 14.8% for the stimulation threshold and 13.5% for sensing. Device malfunctions occurred in 3.7% of cases, both involving electrical resets and neutron-producing radiation (beam energy 10 megaelectron volt (MV) or higher).

Conclusion: Collecting lead parameters in addition to secure malfunctions like electrical restarts and memory erasure revealed a significant proportion of treatment courses with temporary changes, though no correlation with individual treatment plans or adverse events was found. The focus on reducing neutron-producing radiation could be further supported.