Abstract
Background
Local impedance (LI) at a distal tip of the ablation catheter can indirectly measure catheter contact and tissue temperature during radiofrequency catheter ablation (RFCA). LI decreases by RFCA, and a degree of LI drop is correlated with lesion size. However, data on the effects of catheter contact angle on lesion size and LI drop were scarce. This study aimed to evaluate the influence of catheter contact angle on lesion size and LI drop in a porcine experimental study.
Methods
Lesions were created on porcine myocardial left ventricles by the LI-sensing ablation catheter (IntellaNav MiFi OI®). Contact force (CF) was measured using pressure to current transducer (load cell). Radiofrequency ablation was performed with a power of 30 Watt and a duration of 30 seconds. CF (0g, 5g, 10g, 20g, and 30g) and catheter angle (30°, 45°, and 90°) were changed in each set (total 120 lesions, n=8 each). LI rise, LI drop by RF application, and lesion size (maximum lesion width, maximum surface width, and maximum lesion depth) were evaluated.
Results
There was no angular dependence in LI rise in all CF. The values of LI rise increased as CF increased. The LI drop also increased as CF increased in all contact angles. Regarding the difference of catheter angles, LI drop with 90° was lower than those with 30° and 45°in CF 10g, 20g, and 30g, respectively. Maximum lesion width and surface width were larger in 30° and 45° than those in 90°, whereas there were no differences in maximum lesion depth.
Conclusion
LI drop in 90° were significantly lower than those in 45° and 30°. Although lesion depths were not different among the three angles, the absolute values of LI drop were different. Caution should be exercised to comprehend the LI drop with catheter angles.
FUNDunding Acknowledgement
Type of funding sources: None.
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