Lesion Formation by Ventricular Septal Ablation With Irrigated Electrodes - Comparison of Bipolar and Sequential Unipolar Ablation -

Abstract

Background: Ablation of ventricular tachycardia originating from the interventricular septum (IVS) is often limited by the presence of re-entrant pathways deep in the IVS. We compared the efficacy of bipolar ablation vs. sequential unipolar ablation in creating a transmural lesion across the porcine IVS. Methods and Results:Seventeen excised swine hearts were superfused by pulsatile saline flow. Bipolar ablation (at 30 W, 50 W or 70 W for 120 s) was performed between 2 saline-irrigated (20 ml/min) 4-mm tip electrodes, 1 on the left and 1 on the right side of the IVS. Sequential unipolar ablation (at 30 W, 50 W or 70 W for 120 s) was performed on the left and right sides of the IVS with an irrigated-tip catheter. Bipolar ablation produced a narrower, deeper lesion than did unipolar ablation. A transmural lesion was created by sequential unipolar ablation in 7.7%, 8.3% and 0% of tissue preparations and by bipolar ablation in 50.0%, 46.7% and 71.4% of tissue preparations at 30 W, 50 W and 70 W.Conclusions: Bipolar ablation of the IVS was highly effective for creating a transmural IVS lesion. (Circ J 2011; 75: 565 - 570)

Radiofrequency cardiac ablation with catheters placed on opposing sides of the ventricular wall: Computer modelling comparing bipolar and unipolar modes

“…Nagashima et al [2] compared BM and SEUM using saline-irrigated electrodes on excised swine hearts and found that BM produced a higher number of transmural lesions. Sivagangabalan et al [1] also found that BM required fewer ablations to achieve block across ablation lines and created larger lesions in a post infarct ovine model.…”

“…The creation of such deep lesions while needed, cannot be always achieved with unipolar mode (UM) of RF ablation. Recent experimental studies have shown that using two catheters placed on opposing IVS surfaces to deliver RF in the bipolar mode (BM) allows deeper lesions to be created [1,2]. These results suggest that BM could be more effective than UM at eliminating VTs from deep intramural sites.…”

Bipolar Endo-Epicardial Radiofrequency Ablation of Arrhythmia Originating From the Left Ventricular Summit

“…4,5 Lesions created by bipolar energy have more concentrated structure than those created by unipolar energy, because the bipolar ablation affects the vector of RF current, redirecting it towards deep myocardium, and this feature may also limit the collateral damage. This may result in more effective ablation 6 and reduce the risk of complications. Possible damage to coronary arteries within the bipolar RF circuit, however, remains the main limitation of this technique, and the proximity of the LAD and CX may limit bipolar RFCA in LVS.…”

Epicardial Ablation With Irrigated Electrodes

“…23 We compared the efficacy of bipolar ablation vs. sequential unipolar ablation and reported that bipolar ablation of the IVS was highly effective for creating a transmural lesion. 24 In 2 recently reported cases, unipolar RF ablation from the RV and LV aspects of the IVS was ineffective for terminating and preventing VT, but bipolar ablation between the left and right aspects of the IVS opposite the septal scar was effective. 25, 26 Furthermore, Kassenberg et al recently reported a case in which 2 endocardial ablation procedures and an epicardial ablation procedure were unsuccessful, but bipolar RF ablation between an epicardial and endocardial catheter was effective in ablating extrasystoles originating from the RV mid-myocardium.…”