Tomas Zaremba

Risk of Device Malfunction in Cancer Patients with Implantable Cardiac Device Undergoing Radiotherapy: A Population‐Based Cohort Study

Pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) may develop malfunction during external beam radiotherapy (RT). We aimed to describe clinical practice in PM/ICD patients undergoing RT and to assess the rate and predictors of device malfunctions.

The effect of radiotherapy beam energy on modern cardiac devices: an in vitro study.

AIMS Radiotherapy (RT) for malignancies can harm pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). There is some evidence that, besides cumulative dose, the damaging radiation effects increase with beam energy. The aim of this study was to determine whether modern PMs and ICDs are more sensitive to high-energy than to low-energy photon beams. METHODS AND RESULTS Two groups of unused PMs and explanted ICDs (five PMs and one ICD in each) were subjected to irradiations in a phantom with 6 and 18 megavolt (MV) photons, respectively. The devices were exposed to radiation at doses of 2 gray (Gy) daily to simulate two clinical scenarios with the PM/ICD in the RT field. A cumulative dose of 150 Gy was given to each device, corresponding to approximately twice the therapeutic dose. In the 6 MV group, one episode of PM malfunction was detected after reaching 150 Gy. In the 18 MV group, a total of 14 episodes of malfunction were detected starting at 30 Gy in all five PMs. No episodes appeared in the ICD, at the respective treatment groups. This corresponded to a hazard ratio of 9.11 [∼95% confidence interval (CI): 1.04-79.69] by Cox regression analysis between the two groups. In a repeated measures logistic regression model comparing the incidence rate of malfunctions, the odds ratio was 18.29 (∼95% CI: 1.52-219.41). CONCLUSION Photon beam energy plays a considerable role in inducing implantable cardiac device malfunctions. Low-energy RT may be safer in PM/ICD patients despite relatively high radiation dose to the device.

Radiotherapy in patients with pacemakers and implantable cardioverter defibrillators: a literature review

An increasing number of patients with implantable cardiac rhythm devices undergo radiotherapy (RT) for cancer and are thereby exposed to the risk of device failure. Current safety recommendations seem to have limitations by not accounting for the risk of pacemakers and implantable cardioverter defibrillators malfunctioning at low radiation doses. Besides scant knowledge about optimal safety measures, only little is known about the exact prevalence of patients with devices undergoing RT. In this review, we provide a short overview of the principles of RT and present the current evidence on the predictors and mechanisms of device malfunctions during RT. We also summarize practical recommendations from recent publications and from the industry. Strongly associated with beam energy of photon RT, device malfunctions occur at ∼3% of RT courses, posing a substantial issue in clinical practice. Malfunctions described in the literature typically consist of transient software disturbances and only seldom manifest as a permanent damage of the device. Through close cooperation between cardiologists and oncologists, a tailored individualized approach might be necessary in this patient group in waiting time for updated international guidelines in the field.

Cardiac magnetic resonance characteristics in young survivors of aborted sudden cardiac death

PURPOSE We aimed to identify and assess cardiac abnormalities by cardiovascular magnetic resonance (CMR) in a non-ischaemic aborted sudden cardiac death (SCD) population and to establish possible predictors of SCD. METHODS Thirty-six consecutive SCD survivors [median age 37.6 years (IQR 24.1-43.2), 31% female] with no previous cardiac history or evidence of ischaemic heart disease underwent CMR on day 6 (IQR 4-10) after admission. Data on ventricular volumes and the extent of late gadolinium enhancement (LGE) were collected. Systolic strain analysis was performed using feature tracking software. RESULTS Left ventricular (LV) and right ventricular (RV) indexed diastolic volumes were 92.9 ± 28.4 ml/m2 and 94.1 ± 29 ml/m2, respectively. LV ejection fraction (EF) and RV EF were 56.8 ± 10.7% and 53.7 ± 10.7%, respectively. Global peak endocardial longitudinal, circumferential, and radial strain were -17.9 ± 4.28%, -23.2 ± 5.8%, and 32.8 ± 10.6%, respectively. Compared to normal range, global longitudinal endocardial strain, longitudinal epicardial strain, circumferential endocardial strain, radial strain, and circumferential endocardial strain rate were impaired. Median volume of LGE was 0.25% (IQR 0.12-1.12) of the LV myocardium with highest prevalence in the inferolateral wall. Patients with cardiomyopathy diagnosis (n = 16) had lower LV strain rate compared to patients without cardiomyopathy (n = 20). CONCLUSIONS CMR findings in young patients with aborted SCD due to non-ischaemic heart disease seem to be minor. Although only present in small amounts, LGE appears to have a predilection towards the inferolateral wall in this population.