Stereotactic Ablative radiation therapy (SABR) for cardiac arrhythmia: A new therapeutic option?

AIM: Stereotactic ablative radiation therapy (SABR) is used in non-oncologic indications, recently even for cardiac arrhythmias. Thus, aim of this analysis is to review preclinical, early clinical evidences and future direction of the latter new treatment approach. METHOD: A collection of available data regarding SABR and cardiac arrhythmias was made, by Pubmed research and 2 independent researchers, including preclinical and clinical data. A review of ongoing trials was conducted on ClinicalTrials.gov. RESULTS: Preclinical research conducted in animal models showed that a safe and effective noninvasive treatment approach for cardiac arrhythmias could be represented by SABR with a median time of response around 2-3 months. The treatment dose plays a crucial role: the atrioventricular node would seem more radiosensitive than the other cardiac electric zones. Clinical data, such as published case series, case reports and early prospective studies, have already suggested the feasibility, efficacy and safety of SABR (25 Gy in one session) for refractory ventricular arrhythmias. CONCLUSION: Considering the ongoing trials of SABR and new technological improvements in radiotherapy (e.g. hybrid magnetic resonance) and in arrhythmias noninvasive mapping systems, the future analyses will improve the reliability of those preliminary results.

Electroanatomic guidance versus conventional fluoroscopy during transseptal puncture for atrial fibrillation ablation.

INTRODUCTION: Technological advancement in the setting of atrial fibrillation (AF) ablation has decreased radiation exposure and complications associated with the procedure. Yet, transseptal puncture (TSP) remains a challenging step that necessitates accurate guidance. We describe our experience performing TSP under electroanatomic (EA) guidance. METHODS AND RESULTS: The analysis included 145 consecutive EA-guided ablation procedures performed between June 2018 and April 2019 and 145 consecutive standard ablations performed before June 2018. EA guidance utilized the CARTO 3 three-dimensional mapping system to reconstruct anatomic and electrical characteristics of the right atrium and fossa ovalis. Patients with a history of previous cardiac surgery were excluded. For EA-guided procedures, the mean patient age was 60 ± 10 years, 75.2% were male, and 69.0% had paroxysmal AF. Similarly, the mean age for conventional procedures was 60 ± 11 years, 71.0% were male, and 71.7% had paroxysmal AF. The fossa ovalis was detected as a region of low voltage, <0.75 mV. EA guidance yielded shorter fluoroscopy times (EA vs. conventional, 3.6 ± 2.5 vs. 13.5 ± 10.5 min; p < .001) and a lower dose area product than conventional guidance (13 ± 11 Gy* cm2 vs. 28 ± 27 Gy* cm2 ; p < .001). The total procedure duration was similar between groups (146 ± 48 vs. 148 ± 54 min). There were no significant complications related to TSP. CONCLUSION: During AF ablation, TSP with EA guidance facilitated safe access to the left atrium while reducing radiation risk to both patients and operators.

Ablation of atrial fibrillation and esophageal injury: Role of bipolar and unipolar energy using a novel multipolar irrigated ablation catheter.

BACKGROUND: The circular nMARQ ablation catheter is a useful tool for pulmonary vein isolation (PVI). Some studies reported a high incidence of esophageal lesions by using this catheter. OBJECTIVE: The primary aim of this study was to compare the effects on the esophageal wall of bipolar and unipolar energy applied by the nMARQ ablation catheter during AF ablation. METHODS: Forty patients (mean age 53 ± 8 years; 26 [65%] men) were enrolled to perform PVI for symptomatic atrial fibrillation. Thirty patients underwent PVI with the nMARQ catheter (group 1) and 10 patients with the ThermoCool Surround Flow catheter (group 2). The procedures were performed with the CARTO3 system. All patients received an esophageal temperature probe. In group 1, we delivered unipolar energy on the left posterior wall with power between 15 and 18 W or bipolar energy with power at 15 W. In group 2, unipolar energy was delivered on the posterior atrial wall at 20-25 W power. All patients underwent esophagoscopy the day after the procedure. RESULTS: No patients had procedural complications. In group 1, bipolar energy was associated with a lower esophageal temperature increase as compared with unipolar energy (0.6°C [range 0-2.2°C] vs 2.1°C [range 0.8-2.9°C]; P < .001). Unipolar energy was associated with a similar temperature increase in the 2 groups (1.9°C [range 0.8-2.9°C] in group 1 vs 1.7°C [range 0.7-2.9°C] in group 2; P = .49). No patient had esophageal injury. CONCLUSION: The use of the nMARQ catheter for PVI is feasible and safe. The use of 15 W for bipolar energy or 15-18 W for unipolar energy is an optimal strategy to avoid esophageal injury with this new catheter.