Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability

• Published in: Journal of the American Heart Association Vol. 7; no. 15; p. e009070
• Main Authors: Livia, Christopher, Sugrue, Alan, Witt, Tyra, Polkinghorne, Murray D, Maor, Elad, Kapa, Suraj, Lehmann, Helge I, DeSimone, Christopher V, Behfar, Atta, Asirvatham, Samuel J, McLeod, Christopher J
• Format: Journal Article
• Language: English
• Published: England John Wiley and Sons Inc 07.08.2018; Wiley
• Subjects: ablation; direct current ablation; irreversible electroporation; Original Research; Purkinje fibers; ventricular fibrillation; window of vulnerability; ventricular fibrillation; Purkinje fibers; window of vulnerability; direct current ablation; irreversible electroporation; ablation
• ISSN: 2047-9980; 2047-9980
• DOI: 10.1161/JAHA.118.009070

Background The Purkinje network appears to play a pivotal role in the triggering as well as maintenance of ventricular fibrillation. Irreversible electroporation ( IRE ) using direct current has shown promise as a nonthermal ablation modality in the heart, but its ability to target and ablate the Purkinje tissue is undefined. Our aim was to investigate the potential for selective ablation of Purkinje/fascicular fibers using IRE . Methods and Results In an ex vivo Langendorff model of canine heart (n=8), direct current was delivered in a unipolar manner at various dosages from 750 to 2500 V, in 10 pulses with a 90-μs duration at a frequency of 1 Hz. The window of ventricular fibrillation vulnerability was assessed before and after delivery of electroporation energy using a shock on T-wave method. IRE consistently eradicated all Purkinje potentials at voltages between 750 and 2500 V (minimum field strength of 250-833 V/cm). The ventricular electrogram amplitude was only minimally reduced by ablation: 0.6±2.3 mV ( P=0.03). In 4 hearts after IRE delivery, ventricular fibrillation could not be reinduced. At baseline, the lower limit of vulnerability to ventricular fibrillation was 1.8±0.4 J, and the upper limit of vulnerability was 19.5±3.0 J. The window of vulnerability was 17.8±2.9 J. Delivery of electroporation energy significantly reduced the window of vulnerability to 5.7±2.9 J ( P=0.0003), with a postablation lower limit of vulnerability=7.3±2.63 J, and the upper limit of vulnerability=18.8±5.2 J. Conclusions Our study highlights that Purkinje tissue can be ablated with IRE without any evidence of underlying myocardial damage.