1Universitätsklinikum Tübingen Innere Medizin III, Kardiologie und Kreislauferkrankungen Tübingen, Deutschland; 2Universitätsklinikum Tübingen Kinderkardiologie, Pulmologie, Intensivmedizin Tübingen, Deutschland
Background: Bipolar Pulsed Field Ablation with specially designed catheters have been shown to be efficient and safe for pulmonary vein isolation (PVI). However, a new technology of a pulsed field generator enables established contact force-controlled radiofrequency (RF) catheters to apply monopolar pulsed electrical field (PEF) energy for atrial fibrillaton (AF) ablation. We evaluated this novel monopolar PEF ablation technique by creating linear ablation lines beyond PVI for treatment of complex AF patients.
Methods: Patients (n=87, age 65±12 years) referred for re-ablation of AF and presented with recurrence of persistent AF (n=29) or atypical atrial flutter (n=48) after a PVI procedure, or patients with longstanding persistent AF and severe enlarged atrium (n=10) were included in our patient cohort for additional AF substrate ablation with PEF application. After high density voltage mapping of the left atrium with multipolar microelectrode catheters, and de novo PVI performed with RF-energy applications, or re-PVI with PEF (21 patients), additional left atrial linear lesions were performed according to the atrial flutter mechanism or as fibrosis-guided substrate ablation by PEF applications. Only a small group of patients (16%) showed no low voltage areas in the left atrium (bipolar electrograms <0.5mV), however, in the other dominant patient group low voltage areas accounted for 38±31% of the left atrial surface. Using contact force sensing catheter (IntellaNav StablePoint, Boston Scientific, or SmartTouch ST, Biosense Webster), 25A PEF Energy (Centauri, Galvanize) pulses were applied with a minimum of 5g contact force and an interlesion distance ≤5mm for linear lesions beyond the PVs. Before PEF application close-by a coronary artery (lateral mitral line, CTI) 0.2 mg i.v. nitroglycerin was injected.
Results: Complete lines with exclusively PEF applications were 100% for roof lines (n=52), posterior wall isolation (n=18), anterior mitral lines (n=26). Exclusively endocardial PEF application blocked the lateral mitral line in 33 out of 38 cases (87%). Only in five cases additional epicardial RF applications via coronary sinus and endocardial additional RF application were necessary to complete the mitral isthmus block. In 20 out of 21 cases CTI were blocked by linear PEF applications (95%), however, in one case additional RF application became necessary for block due to a very sharp-edged CTI with an unstable catheter position. Besides from one cardiac tamponade, no other serious complication occurred throughout all procedures (no ST segment elevation, no cerebrovascular event). Limited follow-up will be available at the time of presentation.
Conclusion: Catheter ablation of complex atrial fibrillation patients with left atrial linear lesions is performed very efficient and safe with PEF applications by contact force-sensing RF ablation catheters. Especially the high efficacy of exclusively endocardial PEF application for creation of a lateral mitral isthmus block is very promising. However, the long term permanence of the linear lines have to be awaited.