Irrigated Radiofrequency Ablation With Transmurality Feedback Reliably Produces Cox Maze Lesions In Vivo

Comparison of bipolar and unipolar radiofrequency ablation in an in vivo experimental model

“…Our finding that the bipolar ablation device is able to produce transmural lesions in atrial tissue is in accordance with other studies using similar devices, both saline irrigated [14,15] and non-irrigated [13,16]. Most of these reported 100% continuous and transmural lesions.…”

“…In these studies ablation was performed only in atrial tissue in experimental animals, and in one of the studies single layers of atrial myocardium were ablated. Transmural lesions were reported in tissue with a thickness up to almost 10 mm [15]. One earlier study with ablation in atrial myocardium using a prototype of the bipolar device used in the present study reported lesion transmurality slightly less than 100%, consistent with our results [14].…”

“…Thus, the significantly less wide lesions produced with the bipolar ablation device may offer an additional advantage compared to the unipolar device. The lesion width with the bipolar device measured in this study is similar to that reported by others using the same device [15].…”

“…This is described in detail by others [14,15]. Our findings with regard to lesions in thicker myocardium indicate that this method of assessing lesion transmurality is not sufficiently reliable to be used as the sole parameter for transmurality in thick myocardium if ablated only from the epicardial surface in the beating heart.…”

“…The tip of the device is moved over the epicardial surface of the heart 10 -15 mm every second, back and forth at one second intervals over the same tissue for 15 s resulting in an average ablation rate of approximately 1 mm/s. The bipolar device is also described in detail elsewhere [15]; in summary, it incorporates two electrodes on separate arms of a malleable clamping device. Bipolar RF energy is delivered between the two arms.…”