Stereotactic radiosurgery for ablation of ventricular tachycardia.

AIMS: Stereotactic body radiotherapy (SBRT) for ventricular tachycardias (VTs) could be an option after failed catheter ablation. In this study, we analysed the long-term efficacy and toxicity of SBRT applied as a bail-out procedure. METHODS AND RESULTS: Patients with structural heart disease and unsuccessful catheter ablations for VTs underwent SBRT. The planning target volume (PTV) was accurately delineated using exported 3D electroanatomical maps with the delineated critical part of re-entry circuits. This was defined by detailed electroanatomic mapping and by pacing manoeuvres during the procedure. Using the implantable cardioverter-defibrillator lead as a surrogate contrast marker for respiratory movement compensation, 25 Gy was delivered to the PTV using CyberKnife. We evaluated occurrences of sustained VT, electrical storm, antitachycardia pacing, and shock; time to death; and radiation-induced events. From 2014 until March 2017, 10 patients underwent radiosurgical ablation (mean PTV, 22.15 mL; treatment duration, 68 min). After radiosurgery, four patients experienced nausea and one patient presented gradual progression of mitral regurgitation. During the follow-up (median 28 months), VT burden was reduced by 87.5% compared with baseline (P = 0.012) and three patients suffered non-arrhythmic deaths. After the blanking period, VT recurred in eight of 10 patients. The mean time to first antitachycardia pacing and shock were 6.5 and 21 months, respectively. CONCLUSION: Stereotactic body radiotherapy appears to show long-term safety and effectiveness for VT ablation in structural heart disease inaccessible to catheter ablation. We report one possible radiation-related toxicity and promising overall survival, warranting evaluation in a prospective multicentre clinical trial.

Sinus rhythm restoration and arrhythmia noninducibility are major predictors of arrhythmia-free outcome after ablation for long-standing persistent atrial fibrillation: a prospective study.

BACKGROUND: The impact of restoring sinus rhythm (SR) by initial ablation in patients with long-standing persistent atrial fibrillation (LSPAF) is not fully established. OBJECTIVE: The purpose of this study was to investigate the prognostic value of SR restoration at the initial procedure and arrhythmia noninducibility at the final repeat procedure for long-term outcome. METHODS: A total of 203 patients (22% female; age 59 ± 9 years) underwent stepwise catheter ablation for LSPAF. RESULTS: The procedural end-point of SR restoration was achieved in 50% of patients. During follow-up (median 48 months) and after 1.7 procedures per patient, 72% of patients were free from arrhythmia off antiarrhythmic drugs. Failure to restore SR was independently predicted by left atrial (LA) long-axis diameter ≥68 mm (relative risk [RR] 1.55, P = .03], proportion of high-voltage LA sites <20% (RR 1.62, P = .02), and left atrial appendage (LAA) atrial fibrillation cycle length (AFCL) <155 ms (RR 1.5, P = .05). Arrhythmia recurrence after the initial procedure was predicted by SR nonrestoration (RR 2.99, P <.000001) and LAA AFCL ≥155 ms (RR 1.90, P = .0002). Arrhythmia recurrence after the final procedure was predicted by SR nonrestoration at the initial procedure (RR 2.83, P = .0007), persistent AF duration ≥24 months (RR 2.74, P = .002), LAA outflow velocity <40 cm/s (RR 2.21, P = .006), and LAA AFCL ≥155 ms (RR 1.92, P = .02). In 115 patients with repeat procedure(s), failure to achieve arrhythmia noninducibility at the final procedure (19% of patients) was associated with arrhythmia recurrence (RR 8.9, P < .000001). CONCLUSION: SR restoration at the initial procedure and arrhythmia noninducibility at the last repeat procedure were major predictors of arrhythmia-free outcome after ablation for LSPAF.

Long-term results of paediatric radiofrequency catheter ablation: a population-based study.

AIMS: We aimed to evaluate long-term utilization and results of paediatric radiofrequency catheter ablation (RFCA) in a population-based study. METHODS AND RESULTS: Data from all three centres performing paediatric RFCA for the whole population of the Czech Republic between 1993 and 2010 were retrospectively reviewed. A total of 708 ablation procedures in 633 consecutive patients <18 years for 716 different substrates were tracked, with accessory pathways = 439 (61.3%) and atrioventricular nodal reentry tachycardia (AVNRT) = 205 (28.6%) being most frequent. Incidence of RFCA reached 0.049 per 1000 children <18 years of age in the recent era (2006-10). Indications included patient preference (68.0%), drug refractoriness (15.5%), asymptomatic Wolff-Parkinson-White pre-excitation (8.4%), and malignant arrhythmia (6.1%). Median follow-up was 13.7 (interquartile range 5.7-21.5) months. Overall acute/long-term success of the primary procedure was 89.1/77.2% (accessory pathways 87.2/77.7%, AVNRT 98.5/84.4%). Re-ablation was performed in 73 of 163 substrates after a primary unsuccessful ablation resulting in a long-term cumulative efficacy of 96.3%. Between 1993-2005 and 2006-10, procedure/fluoroscopy time decreased from median 154/24 to 105/14 min. (P < 0.001 for both). Serious complications occurred in nine patients (1.4%). CONCLUSION: This population-based study could replicate data from previous single- or multi-centre reports confirming RFCA as a safe method of arrhythmia treatment in children with long-term cumulative efficacy exceeding 90% and significant decrease in the procedure and fluoroscopy time during the study period. The need for RFCA can be estimated at ∼0.05/1000 children <18 years using current indication criteria.