Repeat ablation of refractory ventricular arrhythmias in patients with nonischemic cardiomyopathy: Impact of midmyocardial substrate and role of adjunctive ablation techniques

Abstract

For NICM patients with recurrent, refractory VAs despite previous ablation, effective arrhythmia control can safely be achieved with subsequent ablation, although >1 repeat procedure with adjunctive ablation is often required, especially with MMS.

Successful ablation of ventricular tachycardia arising from a midmyocardial septal outflow tract site utilizing a simplified bipolar ablation setup

“…Our case demonstrates the feasibility of bipolar ablation delivered across the interventricular OT, a site known to be refractory to unipolar ablation 1, 6. Importantly, we were able to carry out Bi-RF using a widely available mapping system (EnSite Precision, Abbott) and preexisting, noninvestigational, non-custom-made equipment, in distinction from prior reports 1, 2, 3, 4. The configuration described provides additional advantages of being able to visualize active and ground ablation catheters simultaneously within the EAM, as well as associated EGMs.…”

“…Notably, recorded PVCs and VT were of differing morphologies, but were similar in overall axis (left or right bundle with right and inferiorly directed axes), suggesting intramural arrhythmogenic source with varying exits from the outflow tract (OT) region 7 . Recognizing that a potentially midmyocardial arrhythmogenic source was present, we planned to utilize techniques to augment RF energy delivery if necessary, including Bi-RF ablation and cooling irrigant with decreased ionic charge (ie, half-normal saline [HNS])3, 8; techniques and associated risks were discussed with the patient in informed consent before the procedure. Detailed EAM was performed in sinus rhythm of the right ventricle (RV) and LV using EnSite Precision EAM (Abbott, Saint Paul, MN).…”

“…Bipolar radiofrequency (Bi-RF) ablation has been utilized to treat atrial and ventricular arrhythmias refractory to standard unipolar RF (Uni-RF) ablation 1, 2, 3, 4, 5, 6. In order to perform Bi-RF, the configuration of an existing Uni-RF circuit is altered, such that another catheter is designated as the grounding connection for the active RF-delivering ablation catheter, instead of an impedance patch.…”

“…In order to perform Bi-RF, the configuration of an existing Uni-RF circuit is altered, such that another catheter is designated as the grounding connection for the active RF-delivering ablation catheter, instead of an impedance patch. This arrangement has usually required use of nonmanufactured, custom-made cables 1, 2, 3, 4, 5. Despite its utility in achieving deeper RF lesions compared to standard Uni-RF ablation, particularly in intramural substrate cases, several limitations exist with this construct: (1) connection of the custom-made cable to the grounding port can be tenuous and prone to malfunction; (2) construction and use of the cable requires technical expertise and is not industry standard, which limits availability; (3) active and ground catheters cannot be simultaneously visualized on the electroanatomic mapping (EAM) system, during mapping or ablation; and (4) other surrogates for confirming contact and stability of the catheters, including visualization of local electrograms (EGMs) and contact force, are absent, thus necessitating greater use of fluoroscopy and intracardiac echocardiography (ICE) 4 .…”

Forging ahead: Update on radiofrequency ablation technology and techniques

“…Promising results from select use of bipolar ablation have been reported in single case or case series formats (Table ). Among others, prior reports document successful ablation of atrial flutters, interseptal ventricular tachycardias and mid‐myocardial ventricular tachycardia substrates utilizing bipolar ablation techniques . Growing clinical experience with use of bipolar ablation in select cases has further corroborated this approach as a safe and effective strategy for arrhythmias refractory to or incompletely treated by standard ablation techniques.…”