Key result
Higher contact force predicts ~16% greater odds of transmural lesion formation in canine ventricular models.
Why the study?
Interlesion gaps and suboptimal transmurality after catheter ablation can reduce efficacy in preventing arrhythmias, prompting evaluation of predictors of transmurality and interlesion distance thresholds.
Effect estimate: OR 1.16 (95% CI 1.03 - 1.3)
p-value: p=0.01
In a canine model, higher contact force predicts transmural ventricular lesions, and paired lesions must be spaced less than 10 mm apart to create contiguous scars.
May inform contact-force and spacing targets in experimental VT ablation; leaves open human translation for durable lesions.
Background Interlesion gaps and transmurality of lesions after catheter ablation can precipitate suboptimal efficacy in preventing arrhythmias. Aims We aim to assess predictors of acute transmural lesion formation and the interlesion distance threshold for creating a continuous, chronic scar after ventricular ablation. Materials and Methods Ablation procedures were performed on 7 canines followed by late gadolinium enhancement MRI (LGE-MRI). Transmurality of lesions was assessed by 2 independent operators. Ablation parameters such as duration (s), power (W), temperature (C), contact force (CF) (g), were collected for each ablation point. After 7-12 weeks, LGE-MRI was performed, followed by euthanasia, and heart excision. Some lesions were created in pair. Lesion pairs were spaced 7-21 mm apart as measured by Electroanatomic mapping (EAM), with different operating parameters (power 35 or 50W, duration of energy delivery 10, 20 or 30s and contact force of 10g or above). We performed a logistic regression analysis to determine predictors of transmural lesion formation. Results Eighty-one radiofrequency ablation were performed in total [33 in the Left ventricle (LV) and 48 in the Right ventricle (RV)]. Higher CF was a significant predictor of transmural lesion formation (β = 0.15, OR = 1.16, 95% CI [1.03 – 1.3], p = 0.01), and lesions delivered in the RV were more frequently transmural than lesions delivered in the LV (β = −2.43, OR = 0.09, 95%CI [0.02 – 0.34], p < 0.001). For the paired analysis, thirty-eight lesions were created contiguously: fourteen connected lesions and twenty-four unconnected lesions. EAM distance was significantly larger in unconnected lesions than connected lesions (16.17 ± 0.92 mm vs. 11.51 ± 0.68 mm, respectively, p < 0.05). We concluded that an interlesion distance of less than 10 mm is required to prevent gap formation. Average volumes in unconnected lesions ( n = 24) at the acute and chronic stages were 0.55 ± 0.11 cm 3 and 0.20 ± 0.02 cm 3 , respectively. On average, lesion volumes were 64% ( p < 0.05) smaller at the chronic stage compared to the acute stage. Among connected lesions ( n = 14), we observed a volume of 1.19 ± 0.8 cm 3 and 0.39 ± 0.15 cm 3 at the acute and chronic stages, respectively. These connected lesions reduced in volume by 67% on average. Conclusion To create contiguous scars on the ventricular endocardial surface, paired lesions should be spaced less than ten millimeters apart. Higher contact force should be used in ventricular ablation to create transmural lesions.
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Hajjar et al. (2022) studied Ventricular ablation lesions (n=7). Radiofrequency catheter ablation was evaluated on Transmural lesion formation predicted by higher contact force (OR 1.16, 95% CI 1.03 - 1.3, p=0.01). Higher contact force significantly predicted transmural lesion formation (OR 1.16), and an interlesion distance of less than 10 mm was required to prevent gap formation in canine ventricular models.
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