Patient Selection for Epicardial Ablation—Part II: The Epicardial Approach and Current Challenges Associated with Epicardial Ablation

Figure 1:. Endocardial–epicardial bipolar ablation configuration. Bipolar ablation across an LV summit midmyocardial circuit may require epicardial access for one of the ablation poles. A and B: Fluoroscopic views (anteroposterior) of two ablation catheters in a bipolar configuration, targeting the LV summit area for this patient. LAO: left anterior oblique; RAO: right anterior oblique.

Figure 2:. Epicardial access—“needle-in-needle” approach. In this stepwise image, an 18-gauge needle (Cook Medical, Bloomington, IN, USA) was first inserted for stability, through which the 21-gauge micropuncture is inserted (asterisk), as seen in the anteroposterior (A) and left lateral (B) projections. After entry was gained into the epicardial space using the micropuncture needle, an 0.18-in guidewire (arrow) was then inserted and epicardial placement was confirmed once the wire hugged the borders of the cardiac silhouette (C). Both needles were removed and a micropuncture dilator was advanced into the pericardial space. An 0.35-in guidewire was placed through the dilator, and the wire was confirmed to be crossing multiple cardiac chambers and again wrapping around the borders of the cardiac silhouette in the left anterior oblique projection (D).

Figure 3:. Displacement of the phrenic nerve by higher-impedance pericardial fluid to facilitate lesion formation. A: Fluoroscopy (anteroposterior view) of a pericardial balloon inflated at the level of the phrenic nerve to displace it and allow for endocardial ablation of the sinus node; however, in this case, endocardial ablation did not successfully suppress the inappropriate sinus tachycardia. We decided to ablate the epicardial sinus node inputs but were unable to reach the epicardial area of interest because of the intrapericardial balloon that was being used to move the phrenic nerve away. B: As such, we decided to infuse intrapericardial fluid to move the phrenic nerve away. However, normal saline led to poor lesion formation and we instead used a high-impedance fluid of D5W to allow for adequate ablation lesion formation while still being able to mechanically displace the phrenic nerve.