Increasing electrode length from 2 to 4 mm during radiofrequency ablation more than doubled lesion volume from 143 to 326 mm3 (P=0.025), while lengths beyond 4 mm produced smaller lesions.
Does increasing electrode size increase lesion volume during radiofrequency catheter ablation in an in vivo dog model?
Optimizing electrode size to 3 or 4 mm during radiofrequency ablation maximizes lesion volume and may improve the effectiveness of arrhythmia ablation.
Absolute Event Rate: 326% vs 143%
p-value: p=0.025
Radiofrequency current is a promising alternative to high voltage direct current defibrillator discharges for catheter ablation of arrhythmias. However, lesions produced with radiofrequency current are relatively small and use of high power is limited by the impedance rise that occurs with desiccation of tissue and coagulum formation. The effect of electrode size on radiofrequency ablation was assessed by comparing results of radiofrequency application using a standard 6 French electrode catheter (distal electrode 2 mm in length) to those using catheters modified with longer distal electrodes (3, 4, 6, 8, and 10 mm in length). Radiofrequency ablation was performed at 47 left ventricular endocardial sites in 20 anesthetized dogs. A constant power of 13.3 +/- 1.3 watts at 550 kHz was applied between the distal catheter electrode and a skin electrode until a total of 500 joules had been delivered or a rise in impedance occurred. Increasing electrode length from 2 to 4 mm more than doubled lesion volume from a mean of 143 to 326 mm3 (P = 0.025). Increasing electrode length beyond 4 mm produced progressively smaller lesions (157 mm3, 155 mm3, and 67 mm3 for 6-, 8-, and 10-mm electrode lengths, respectively). Impedance rise was significantly less likely with larger electrodes and took longer to occur. Increasing the size of electrodes used for radiofrequency ablation allows application of higher power without an impedance rise. Optimizing electrode size (3 or 4 mm in this study) results in larger lesions and may improve the effectiveness of radiofrequency ablation of arrhythmias.
Langberg et al. (Mon,) conducted a other in Arrhythmias (n=20). Modified catheters with longer distal electrodes (3-10 mm) vs. Standard 6 French electrode catheter (2 mm length) was evaluated on Lesion volume (p=0.025). Increasing electrode length from 2 to 4 mm during radiofrequency ablation more than doubled lesion volume from 143 to 326 mm3 (P=0.025), while lengths beyond 4 mm produced smaller lesions.
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