Linear accelerator-based stereotactic arrhythmia radioablation for paroxysmal atrial fibrillation in elderly: a prospective phase II trial

Abstract

Aims: Stereotactic arrhythmia radioablation (STAR) is a novel therapeutic approach for cardiac arrhythmias. The aim of this trial is to investigate the feasibility of STAR for the treatment of paroxysmal atrial fibrillation (AF) in elderly patients.

Methods and results: Inclusion criteria were age >70 years, symptomatic AF, antiarrhythmic drugs failure, or intolerance. All patients underwent to 4D cardiac computed tomography simulation. The clinical target volume was identified in the area around pulmonary veins (PV). Stereotactic arrhythmia radioablation was performed with a total dose of 25 Gy (single fraction) delivered in 3 min. Twenty patients were enrolled and 18 underwent STAR. One patient withdrew informed consent before treatment and one patient was excluded due to unfavourable oesophagus position. With a median follow-up (FU) of 16 months (range 12-23), no acute toxicity more than Grade 3 was reported. Five patients had a Grade 1 oesophagitis 24 h after STAR; eight patients had an asymptomatic Grade 1 pericardial effusion, and one patient had a torsade de pointes treated effectively by electrical cardioversion and subsequent cardiac implantable cardioverter-defibrillator implantation. Most patients had a significant reduction in AF episodes. Five patients, due to arrhythmias recurrences after STAR, performed electrophysiological study documenting successful PV isolation. Finally, a significant improvement of quality of life was documented (48 ± 15 at enrolment vs. 75 ± 15 at 12 months FU; P < 0.001).

Conclusion: The present phase II trial demonstrated the feasibility of STAR in paroxysmal AF elderly patients and its potential role in increasing the quality of life. Surely, more robust data are needed about safety and efficacy.

Trial registration: ClinicalTrials.gov: NCT04575662.

Keywords: Atrial fibrillation; Elderly; Pulmonary vein isolation; Stereotactic arrhythmia radioablation.

Graphical Abstract

Figure 1

Flow diagram regarding the STAR clinical trial.

Figure 2

Atrial fibrillation episodes documented during 15-day ECG-Holter monitoring.

Figure 3

Electroanatomic mapping of the left atrium using CARTO System and Pentaray catheter. (A) Pentaray catheter inserted into the right superior pulmonary vein documenting the absence of electrical potentials. (B) Pentaray catheter inserted into the left inferior pulmonary vein documenting the absence of electrical potentials. (C) Pentaray catheter inserted into the left superior pulmonary vein documenting the absence of electrical potentials. (D) Pentaray catheter inserted into the right inferior pulmonary vein documenting the absence of electrical potentials. (E) Left lateral view of the left atrium. (F) Anterior view documenting a low-voltage area on the roof of the left atrium. This area was the site of atrial tachycardia.

Figure 4

Electroanatomic mapping of the left atrium using CARTO System and Pentaray catheter. (A) Pentaray catheter inserted into the left superior pulmonary vein documenting the absence of electrical potentials. (B) Pentaray catheter inserted into the left inferior pulmonary vein documenting the absence of electrical potentials. (C) Pentaray catheter inserted into the right inferior pulmonary vein documenting the absence of electrical potentials. (D) Pentaray catheter inserted into the right superior pulmonary vein documenting the absence of electrical potentials. (E) Right and left atrial electroanatomic mapping.

Figure 5

Electroanatomic mapping of the left and right atrium using CARTO System and Octaray catheter. (A) Octaray catheter inserted into the left superior pulmonary vein documenting the absence of electrical potentials. Arrows represent the areas close to oesophagus and left bronchus. (B) Octaray catheter inserted into the left inferior pulmonary vein documenting the absence of electrical potentials. (C) Octaray catheter inserted into the right superior pulmonary vein documenting the absence of electrical potentials. (D) Octaray catheter inserted into the right inferior pulmonary vein documenting the absence of electrical potentials. (E) Right and left atrial electroanatomic mapping.

Figure 6

Electroanatomic mapping of the left atrium using CARTO System and Octaray catheter. (A) Octaray catheter inserted into the left superior pulmonary vein documenting the absence of electrical potentials. (B) Octaray catheter inserted into the left inferior pulmonary vein documenting the absence of electrical potentials. (C) Octaray catheter inserted into the right superior pulmonary vein documenting the absence of electrical potentials. (D) Octaray catheter inserted into the right inferior pulmonary vein documenting the absence of electrical potentials.

Figure 7

Electroanatomic mapping of the left atrium using CARTO System and Pentaray catheter. (A) Octaray catheter inserted into the left superior pulmonary vein documenting the absence of electrical potentials. (B) Octaray catheter inserted into the left inferior pulmonary vein documenting the absence of electrical potentials. (C) Octaray catheter inserted into the right superior pulmonary vein documenting the absence of electrical potentials. (D) Octaray catheter inserted into the right inferior pulmonary vein documenting the absence of electrical potentials.