Feasibility Study on Cardiac Arrhythmia Ablation Using High-Energy Heavy Ion Beams

Abstract

High-energy ion beams are successfully used in cancer therapy and precisely deliver high doses of ionizing radiation to small deep-seated target volumes. A similar noninvasive treatment modality for cardiac arrhythmias was tested here. This study used high-energy carbon ions for ablation of cardiac tissue in pigs. Doses of 25, 40, and 55 Gy were applied in forced-breath-hold to the atrioventricular junction, left atrial pulmonary vein junction, and freewall left ventricle of intact animals. Procedural success was tracked by (1.) in-beam positron-emission tomography (PET) imaging; (2.) intracardiac voltage mapping with visible lesion on ultrasound; (3.) lesion outcomes in pathohistolgy. High doses (40–55 Gy) caused slowing and interruption of cardiac impulse propagation. Target fibrosis was the main mediator of the ablation effect. In irradiated tissue, apoptosis was present after 3, but not 6 months. Our study shows feasibility to use high-energy ion beams for creation of cardiac lesions that chronically interrupt cardiac conduction.

Inducibility of Ventricular Arrhythmia 1 Year Following Treatment with Heavy Ion Irradiation in Dogs with Myocardial Infarction

“…In the most recent report of high-energy carbon ions (40-55 Gy) for ablation of cardiac tissue in pigs, no damage of the esophagus, trachea, phrenic nerves, or coronary arteries was observed during 6 months of follow-up. 30 In our previous study on the dose-dependent efficacy of the carbon ion beam, administration of ࣙ10 Gy to the rabbit heart increased Cx43 levels. 6 The administration of 15 Gy did not adversely affect the beagles' general health, induce novel arrhythmias, or cause cardiac malignancies, as observed at the 1-year follow-up.…”

Noninvasive Cardiac Radiation for Ablation of Ventricular Tachycardia

“…This therapy has resulted in late myocardial fibrosis and electrically inert tissue without evidence of acute or subacute injury to nearby tissues during 6 months of follow-up. 8,9 Clinical case reports have shown the feasibility of the use of SBRT for this purpose. 10,11 …”

“…23 SBRT has the potential to overcome these challenges. 8,9 In this case series, we combined noninvasive mapping (electrocardiographic imaging) and noninvasive ablation (SBRT) to treat patients with refractory ventricular tachycardia.…”

Innovations in Clinical Cardiac Electrophysiology: Challenges and Upcoming Solutions in 2018 and Beyond

“…This modality was investigated in an animal study and showed a dose-dependent reduction in voltage on mapping and the presence of fibrosis and hemorrhage on histology at treated sites, respectively. 83 In another study, photon beams successfully ablated the atrioventricular node in pigs. However, while the coronary arteries remained intact, there was apoptosis at the sites of myocardial beam entry.…”