Key result
Very-high-power short-duration ablation creates ~12% wider lesions than conventional ablation with shallower depth.
Why the study?
Intramural or epicardial arrhythmogenic substrates contribute to RF catheter ablation failure, necessitating analysis of factors affecting lesion dimensions at similar ablation index values.
Absolute Event Rate: 5.83% vs 5.19%
p-value: p=<0.001
VHP-SD may yield more stable lesions at high impedance; leaves open whether wider-shallower geometry improves clinical outcomes.
INTRODUCTION: Intramural or epicardial locations of the arrhythmogenic substrate are regarded as one of the main reasons for radiofrequency (RF) catheter ablation failure. This study aims to conduct a comprehensive analysis of various factors including baseline impedance, irrigant and electrode configuration at similar ablation index (AI) value. METHODS: In 12 ex vivo swine hearts, RF ablation was performed at a target AI value of 500 and a multistep impedance load (100-180 Ω) in 4 settings: (1) conventional unipolar configuration with an irrigant of normal saline (NS); (2) conventional unipolar configuration with an irrigant of half normal saline (HNS); (3) bipolar configuration with an irrigant of NS; (4) sequential unipolar configuration with an irrigant of NS. The relationships between lesion dimensions and above factors were examined. RESULTS: Baseline impedance had a strong negative linear correlation with lesion dimensions at a certain AI. The correlation coefficient between baseline impedance and depth, width, and volume were R = -0.890, R = -0.755 and R = -0.813, respectively (p < .01). There were 10 (total: 10/100, 10%; bipolar: 10/25, 40%) transmural lesions during the whole procedure. Bipolar ablation resulted in significantly deeper lesion than other electrode configurations. Other comparisons in our experiment did not achieve statistical significance. CONCLUSION: There is a strong negative linear correlation between baseline impedance and lesion dimensions at a certain AI value. Baseline impedance has an influence on the overall lesion dimensions among irrigated fluid and ablation configurations. Over a threshold impedance of 150 Ω, the predictive accuracy of AI can be compromised.
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Jiang et al. (2022) studied Ex vivo porcine heart model for radiofrequency ablation (n=120). Very-high-power short-duration (v-HPSD) ablation vs. Conventional power-controlled (PC) ablation was evaluated on Mean superficial diameter of ablation lesion (p=<0.001). Very-high-power short-duration ablation produced significantly wider but shallower lesions compared to conventional power-controlled ablation, and demonstrated greater stability in lesion volume at higher impedance levels.
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