Epicardial box lesion using bipolar biparietal radiofrequency and multimodality scar evaluation—a case series

Abstract

Background Surgical epicardial AF ablation can be performed as a stand-alone (thoracoscopic) procedure or concomitant to other cardiac surgery. In hybrid AF ablation thoracoscopic surgical epicardial ablation is combined with a percutaneous endocardial ablation. The Medtronic Gemini-S clamp is a surgical tool that uses irrigated bipolar biparietal RF energy applied with two clamp lesions that overlap to create one epicardial box lesion including the posterior LA wall and the pulmonary veins. Case summary We describe three patients with therapy-refractory persistent AF and different stages of atrial remodelling in whom the Medtronic Cardioblate Gemini-S Irrigated RF Surgical Ablation System was used for hybrid AF ablation. Acute endocardial validation at the end of the hybrid ablation revealed a complete box lesion in all three cases. At 2-year follow-up, two out of three patients had recurrence of atrial arrhythmias. Invasive electro-anatomical mapping confirmed persistence of the box lesion, and the mechanism of arrhythmia recurrence in both patients was unrelated to posterior left atrium or the pulmonary veins. The third patient has been without arrhythmia symptoms since the ablation procedure. A 3D late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) illustrates the ablation scar non-invasively in two cases. Discussion Thoracoscopic biparietal RF AF ablation with the Medtronic Cardioblate Gemini-S Irrigated RF Surgical Ablation System results in permanent transmural scar formation, irrespective of the stage of atrial remodelling, as shown in this small population by means of multimodality scar evaluation.

Hybrid atrial fibrillation ablation

“…Using irrigated (wet) energy ensures a more controlled way of heating tissue by continuously adjusting its power output to tissue impedance and cooling the tissue surface by adding saline, whereas non-irrigated (dry) RF energy sources only heat affected tissue. Therefore, the use of non-irrigated RF ablation devices can overcome the possible side effects of over-heating, such as microbubbles, tissue coagulum and charring ( 26 ).…”

Multimodality Cardiovascular Imaging for Totally Video-Guided Thorascopic Cardiac Surgery

“…Three-dimensional late gadolinium enhancement MRI is used to evaluate the extent of ablation scar in patients undergoing hybrid atrial fibrillation (AF) ablation combined with thorascopic epicardial ablation with a percutaneous endocardial ablation [ 30 ]. The combination of cardiovascular MRI angiography and pulmonary perfusion allows for assessment of the anatomical stenosis of the pulmonary veins and its hemodynamic impact on the pulmonary parenchymal, which was conducive to evaluating the patency of the reestablished passage in such cases when performing the Warden procedure [ 31 ].…”

Exploring the essential aspects of the hybrid approach for atrial fibrillation

“…Compared to dry, non-irrigated RF devices, irrigated (wet) RF generates larger and more effective ablation lesions with evenly applied energy delivery that, in our experience, result in reliable transmural lesions and a more controlled way of heating the tissue. 43,44 Subsequently, it is suggested that the possible side effects of overheating including the formation of microbubbles, tissue coagulation and charring are prevented. Therefore, the most optimal technique would be to use an irrigated biparietal bipolar RF clamping device that can be used solely from the left side of the thorax, since this also allows for an adequate view of the LAA.…”

“…As such, transvenous endocardial ablation of triggered activity arising from the PVs is not only a safe, but also a very effective rhythm control strategy for patients with pAF and yields successful rhythm control outcomes exceeding 80%. 43 Unfortunately, results for persAF are far less satisfactory and success rates, independent of the ablation strategy applied, do not exceed 45%. 44 While several endocardial substrate modification techniques besides PVI only have been tested, [45][46][47] none of them were associated with high success rates and they may even be pro-arrhythmic if lesions fail to be transmural.…”