Atrial Fibrillation: Update on Ablation Strategies and Technology

Long-term symptom improvement and patient satisfaction following catheter ablation of supraventricular tachycardia: insights from the German ablation registry

Aims

To analyse outcomes of supraventricular tachycardia (SVT) ablations performed within a prospective German Ablation Quality Registry.

Methods and results

Data from 12 566 patients who underwent catheter ablation of SVT between January 2007 and January 2010 to treat atrial fibrillation (AFIB, 37.2% of procedures), atrial flutter (AFL, 29.9%), atrioventricular nodal re-entrant tachycardia (AVNRT, 23.2%), atrioventricular re-entrant tachycardia (6.3%), and focal atrial tachycardia (AT, 3.4%) were prospectively collected. Patients were followed for at least 1 year. The periprocedural success rate was 96.3%, ranging from 84.3% (focal AT) to 98.9% (AVNRT). Kaplan-Meier mortality estimate at 1 year was 1.4% overall, and as high as 2.6% in the AFL group and 2.8% in the focal AT group. Recurrence of ablated or another symptomatic SVT was observed in 3783 (32.6%) of patients, ranging from 17.2% (AVNRT) to 45.6% (AFIB). Repeat ablation was performed in 12.0% of patients. After 1 year, 74.1% of survivors perceived ablation therapy as successful, 15.7% as partly successful, and 9.6% as unsuccessful. Even in those patients with arrhythmia recurrence, 76.0% perceived ablation as successful or partly successful and 89.6% would still undergo repeat ablation in the same institution.

Conclusion

Ablation therapy for SVT is a safe procedure bringing symptomatic improvement and satisfaction to three quarters of patients after 1 year. Even in patients with arrhythmia recurrence, a high satisfaction level and adherence to the ablating institution could be documented. Strikingly high mortality and stroke rates in follow-up were observed in AFL patients, who apparently need consistent long-term anticoagulation and more medical attention.

A Review of Therapeutic Ablation Modalities

Understanding basic science and technical aspects is essential for scientists and engineers to develop and enhance ablative modalities, and for clinicians to effectively apply therapeutic ablative techniques. An overview of ablative modalities, anatomical locations, and indications for which ablations are performed is presented. Specifically, basic concepts, parameter selection, and underlying biophysics of tissue injury of five currently used therapeutic ablative modalities are reviewed: radiofrequency ablation (RFA), cryoablation (CRA), microwave ablation (MWA), high-intensity focused ultrasound (HIFU), and chemical ablation (CHA) (ablative agents: acetic acid, ethanol, hypertonic sodium chloride, and urea). Each ablative modality could be refined for expanding applications, either independently or in combination, for future therapeutic use.