B-PO04-135 PERCUTANEOUS AND THORACOTOMY BASED SINUS NODE ABLATION USING NANOSECOND PULSED ELECTRIC FIELDS

Abstract

Sinus node (SN) modification/ ablation is a treatment option for inappropriate sinus tachycardia. It is often achieved using radiofrequency ablation which is slow given the point to point nature of treatments. Nanosecond pulse electric fields (nsPEF) are an emerging, rapid energy delivery modality which offers tissue selectivity. We explored whether acute SN ablation can be achieved with nsPEF. In two canine models, general anesthesia was administered along with paralytics. Pericardial access was obtained percutaneously in one animal and via thoracotomy in the other (Fig 1A, 1D). The area of earliest right atrial activation was identified. Electrograms were recorded before and after nsPEF energy delivery near the SN using a CellFX™ generator (Pulse Biosciences, Hayward, CA). SN ablation was achieved in both animals after delivery of 10-20 Joules of energy via nsPEF. Total duration of nsPEF sequences in each animal was <1 min. There was absence of atrial electrograms with a junctional escape rhythm in the first animal (Fig 1B, 1C) after monopolar nsPEF. Atrial activity from a left sided focus was seen in the second animal (Fig 1E, 1F) after bipolar nsPEF. Phrenic capture persisted after both sinus node ablations post paralytic withdrawal. All changes persisted beyond 30 minutes of energy delivery after which the animals were euthanized. In acute canine experiments, energy delivery via nsPEF was able to quickly ablate the SN percutaneously and via thoracotomy. nsPEF effect on cardiac tissue was demonstrated functionally without requiring histology.