Irreversible Intracardiac Defibrillator Circuit Damage Induced by Pulsed-Field Ablation: Mechanistic Insights

Figures

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  Figure 1. Overview of the pulsed-field ablation procedure in case 1. A: A 20-electrode catheter (ReBoot) in the CS and lateral RA. High-frequency noise appeared on the distal CS electrodes immediately after the first pulsed-field ablation application in the LIPV, resulting in the complete loss of electrogram signals. B: Fluoroscopy (left) and CARTO 3 map (right) showing close proximity between ReBoot distal electrodes and VARIPULSE catheter during LIPV ablation. The nonfunctional electrodes are marked with yellow stars. Unipolar recordings demonstrate isolated CS 1 electrode signal loss with preserved CS 2. C: CS venography showing initial malposition in the vein of Marshall (red arrow). CS = coronary sinus; LAO = left anterior oblique; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; RA = right atrium; RL = right lateral; SVC = superior vena cava.

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  Figure 2. Overview of the pulsed-field ablation (PFA) procedure in case 2. A: ReBoot catheter in CS and lateral RA. High-frequency noise was observed on RA electrodes 5 and 6 (RA 5–6) after the first RSPV PFA application. B: CARTO 3 map showing VARIPULSE proximity to RA 5–6 near the SVC. C: Preprocedural computed tomography (right) demonstrates close proximity between the RSPV and SVC (0.6 mm). Fluoroscopy (left) shows the RA 6 positioned near the VARIPULSE catheter. The RA 5, which became nonfunctional after PFA, is indicated by a yellow star. Unipolar recordings show signal loss at RA 5 with preserved RA 6. AP = anteroposterior view; CS = coronary sinus; LA = left atrium; LL = left lateral view; RA = right atrium; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein; SUP = superior view; SVC = superior vena cava.

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  Figure 3. Intracardiac defibrillator circuitry during pulsed-field ablation. A: Normal current flows from the electrode catheter through the relay and resistor to the EP-LAB; yellow arrows indicate the normal direction. B: Case 1: a high-voltage pulse causes excessive voltage in the relay and resistor, leading to irreversible damage. C: Case 2: although the relay and resistor sections of the electrode catheter exposed to high voltage remained intact, activation of the surge-protection circuit discharged an excessive current to the adjacent electrode, damaging its relay and resistor components. The orange arrows indicate the flow of high-voltage current during pulsed-field ablation in both panels B and C. DEF = defibrillator; ECG = electrocardiogram; SW = switch.