High efficacy and safety of pulsed electrical field ablation via contact force-controlled radiofrequency catheters for atrial fibrillation ablation with linear lesions in the left atrium

Abstract Background Pulsed Field Ablation have been shown to be efficient and safe for Pulmonary vein isolation (PVI) in catheter ablation of atrial fibrillation (AF). The bipolar application of pulsed electrical energy for electroporation of myocardium has been established with specially designed catheters, which are not used for linear ablation. Purpose We evaluated a novel monophasic PEF ablation technique applied by commercially available CF-controlled catheters for linear ablation lines beyond PVI for treatment of complex AF patients. Methods Patients (n=31, age 64±12 years, 29% females, BMI 29±4) referred for re-ablation of AF and presented with recurrence of persistent AF (n=13) or atypical atrial flutter (n=14) after a PVI procedure, or patients with longstanding persistent AF and severe enlarged atrium (n=4) were included in our patient cohort for additional AF substrate ablation with PEF applications. After high density voltage mapping of the left atrium with multipolar microelectrode catheters, and PVI, or re-PVI was completed (8 patients), additional left atrial linear lesions were performed according to the atrial flutter mechanism or as fibrosis-guided substrate ablation. All but one patient showed low voltage areas (bipolar electrograms <0.5mV) in 35±31% of the left atrial surface. Using contact force sensing catheters, maximal PEF energy pulses were applied with a minimum of 5g contact force and an interlesion distance ≤6mm. Performed linear lesions were left atrial roof line, lateral mitral isthmus line, anterior mitral line, left posterior wall isolation, and cavotricuspid isthmus (CTI) line. Before PEF application close-by a coronary artery (lateral mitral line, CTI) nitroglycerie 0.2mg i.v. was injected. Results Complete lines with exclusively PEF applications and proofed bidirectional conduction block were 100% for roof lines (n=20), posterior wall isolation (n=8), anterior mitral lines (n=10). Exclusively endocardial PEF applications blocked the lateral mitral line in 14 out of 16 cases (88%). Only in two cases additional epicardial RF applications via coronary sinus and endocardial additional RF applications were necessary to complete the mitral isthmus block. In 7 out of 8 cases CTI were blocked by linear PEF applications (88%), however, in one case additional RF applications became necessary. No ECG ST segment elevation was recorded. No serious complications occurred throughout all procedures. Follow up will be available at presentation time. Conclusion Catheter ablation of complex AF patients with linear lesions is performd very efficient and safe with PEF applications by CF-sensing RF ablation catheters. Especially the high efficacy of exclusively endocardial PEF applications for creation of a lateral mitral isthmus block is very promising. However, the long term permanence of the linear lines have to be awaited.