Key result
The ablation index was significantly lower at touch-up sites compared to control sites (277.2 vs 350.1, p<0.0001), suggesting an optimal target value of 350 for superior vena cava isolation.
Why the study?
Ablation index is useful for durable pulmonary vein isolation in atrial fibrillation, but no study had reported the optimal ablation index value for superior vena cava isolation.
What is the optimal Ablation Index value for superior vena cava isolation in patients with atrial fibrillation?
Observational (n=36)
What is the optimal Ablation Index value for superior vena cava isolation in patients with atrial fibrillation?
The optimal Ablation Index value for superior vena cava isolation in atrial fibrillation patients is 350, with a minimum of 308 required to prevent reconnections.
AI ≥350 may optimize SVC isolation; hypothesis-generating and requires prospective validation before practice change.
Background The ablation index (AI) has been reported to be useful for a durable pulmonary vein isolation (PVI) to treat atrial fibrillation (AF). No study has reported the optimal AI value for the SVC isolation (SVCI). In this study, we aimed to investigate the optimal AI for the SVCI. Methods Thirty-six AF patients who underwent an initial SVCI were enrolled. Ablation was performed at a total of 549 points. The sites where dormant conduction was induced or additional ablation was needed were defined as touch-up sites (n=36). We compared the energy deliver time, power, CF, Force-Time Integral (FTI), and AI between the touch up sites and control sites (n=513). Results The median RF delivery time, power, CF, and FTI were all significantly lower at the touch up sites (touch up sites vs. control sites; energy delivery time, sec, 20.3[12.3-21.7] vs. 21.6[19.8-25.2], p=0.0003; power, W, 23.5[15-24] vs. 24[20-25], p<0.0001; CF, g, 7[6-10.8] vs. 11[9-15], p<0.0001; FTI, 126.5[99.3-208.8] vs. 244[183.5-340.5], p<0.0001). The AI also was significantly lower at the Touch up sites (touch up sites vs. control sites; AI, 350.1±43.6 vs. 277.2±21.8, p<0.0001). The median value of the AI at the control sites was 350 and no reconnections were seen where the minimum AI value was more than 308. Conclusion The AI value at the touch up sites was significantly lower than that at the control sites. The optimal AI value for the SVCI should be 350, and at least 308 would be needed.
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Kawano et al. (2020) conducted an observational in Atrial fibrillation (n=36). Touch-up sites (sites with dormant conduction or needing additional ablation) vs. Control sites was evaluated on Ablation Index (AI) (p=<0.0001). The ablation index was significantly lower at touch-up sites compared to control sites (277.2 vs 350.1, p<0.0001), suggesting an optimal target value of 350 for superior vena cava isolation.
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