Local Calcium Chloride Infusion Enhances Acute and Chronic Efficacy of Ventricular Pulsed-Field Ablation

Pulsed-field ablation (PFA) offers myocardial selectivity with minimal thermal injury, but depth for ventricular lesions may be insufficient or heterogeneous at clinically tolerable field strengths. Calcium electroporation-local calcium chloride (CaCl₂) infusion after PFA-may amplify electroporation-mediated cell death while maintaining low energy settings.

To determine whether immediate post-PFA CaCl₂ infusion enhances acute and chronic ventricular lesion formation in vivo.

Nine swine underwent focal ventricular PFA (750-1000 V, biphasic, 20 μs × 50 pulses, 200 ms interpulse) via an irrigated focal catheter and benchtop electroporator. Immediately post-PFA, lesions were randomized to saline, 0.2 g Ca, or 0.4 g Ca infused locally through the catheter tip. Acute hearts were explanted for TTC analysis; surviving animals were studied at 7 days for chronic lesion geometry.

Among 41 acute lesions (17 control, 12 Ca 0.2 g, 12 Ca 0.4 g), Ca 0.4 g increased dark-zone depth (3.5 ± 1.4 vs. 2.3 ± 0.8 mm; p = 0.038) and pale-zone depth (2.6 ± 1.3 vs. 1.3 ± 0.8 mm; p = 0.011) versus control. At 7 days (n = 33 lesions), Ca 0.4 g produced larger scars than control (width 11.6 ± 2.1 vs. 10.0 ± 1.9 mm; p = 0.027; depth 4.2 ± 1 vs. 3.0 ± 0.8 mm; p < 0.001; volume 193.6.4 ± 82.3 vs. 109.4 ± 48.2 mm³; p = 0.001).

Local CaCl₂ infusion after ventricular PFA significantly augments acute electroporation effect and chronic lesion size at low output, supporting facilitated PFA as a strategy for deeper, more durable ventricular ablation.