Bipolar ablation involving coronary venous system for refractory left ventricular summit arrhythmias

Abstract

Background: Catheter ablation of premature ventricular complexes (PVCs) and ventricular tachycardia (VT) from the left ventricular summit (LVS) may require advanced ablation techniques. Bipolar ablation from the coronary veins and adjacent endocardial structures can be effective for refractory LVS arrhythmias.

Objective: The aim of this study was to investigate the outcomes of bipolar ablation performed between the coronary venous system and adjacent endocardial left ventricular outflow tract (LVOT) or right ventricular outflow tract (RVOT).

Methods: This multicenter study included consecutive patients with LVS PVC/VT who underwent bipolar ablation between the anterior interventricular vein (AIV) or great cardiac vein (GCV) and the endocardial LVOT/RVOT after failed unipolar ablation. Ablation was started with powers of 10-20 W and uptitrated to achieve an impedance drop of at least 10%. Angiography was performed in all cases to confirm a safe distance (>5 mm) of the catheter from the major coronary arteries.

Results: Between 2013 and 2023, bipolar radiofrequency ablation between the AIV/GCV and the adjacent LVOT/RVOT was attempted in 20 patients (4 female; age 57 ± 16 years). Unipolar ablation from sites of early activation (AIV/GCV, LVOT, aortic cusps, RVOT) failed to effectively suppress the PVC/VT in all subjects. Bipolar ablation was delivered with a maximum power of 30 ± 8 W and total duration of 238 ± 217 s and led to acute PVC/VT elimination in all patients. No procedural-related complications occurred. Over a follow-up period of 30 ± 24 months, the freedom from arrhythmia recurrence was 85% (1 recurrence in the VT group and 2 in the PVC group). PVC burden was reduced from 22% ± 10% to 4% ± 8% (P <.001).

Conclusion: In cases of LVS PVC/VT refractory to unipolar ablation, bipolar ablation between the coronary venous system and adjacent endocardial LVOT/RVOT is safe and effective if careful titration of power and intraprocedural angiography are performed to ensure a safe distance from the coronary arteries.

Keywords: Ablation techniques; Catheter ablation; Intramural; Mapping; Radiofrequency; Ventricular arrhythmia.

Figure 1

Twelve-lead morphology of the premature ventricular complexes/ventricular tachycardias.

Figure 2

Left ventricular summit premature ventricular complex (PVC) eliminated by bipolar radiofrequency ablation from the left ventricular outflow tract (LVOT) and coronary venous system after failed standard ablation using EnSite (Abbott, St. Paul, MN). Earliest activation was recorded in the great cardiac vein (GCV)/anterior interventricular vein (AIV) junction (–40 ms), whereas the earliest endocardial site was the subaortic LVOT, below the left coronary cusp (–20 ms). Ablation from the GCV/AIV junction was limited by impedance and temperature rise, and ablation from the earliest LVOT site resulted in only transient suppression. One single bipolar radiofrequency application (20 W, 60 s) from LVOT (Abl1; active catheter) to GCV/AIV (Abl2; return catheter) resulted in durable PVC suppression. CS = coronary sinus; ECG = electrocardiogram; LAO = left anterior oblique; RAO = right anterior oblique.

Figure 3

LVS PVC eliminated with bipolar ablation between the GCV and left coronary cusp after failed standard ablation using CARTO (Biosense Webster, Diamond Bar, CA). A: Clinical PVC morphology. B: Activation map with an ablation catheter at the point of earliest activation. C: Pacemapping from the point of earliest activation with a 98.2% match in the PASO^TM module. D: Earliest activation time (44 ms) with the sensing catheter located in the left coronary cusp. E: Fluoroscopic view of the location of the ablation catheters during bipolar ablation. F: Electroanatomic map showing the location of the ablation catheters during bipolar ablation. G: Suppression of PVCs during bipolar ablation delivery Abbreviations as in Figure 2.

Figure 4

Bipolar ablation between LVOT and septal perforator vein. Patient with cardiac sarcoidosis presenting with incessant bigeminy and symptomatic with dyspnea. Activation mapping showed earliest activation at the first septal perforator vein (–20 ms pre-QRS). Unipolar ablation from the LVOT opposite the intramural catheter and from the earliest site within the perforator vein resulted in only transient PVC suppression. Bipolar ablation from LVOT to the septal vein achieved PVC elimination (distance between active catheter and return catheter measured at 13 mm). Abbreviations as in Figure 2.

Figure 5

Multipolar ablation using an irrigated ablation catheter and multielectrode mapping catheter (EPstar). Earliest local ventricular activation was recorded in the GCV (42 ms pre-QRS), but the ablation catheter could not be advanced to this site, and endocardial ablation from the LVOT was unsuccessful. Therefore, ablation was performed between the LVOT and electrodes 5 and 6 of the EPstar catheter, which were connected to the ground port of the generator via jumper cables. This resulted in successful and durable PVC suppression. Abbreviations as in Figure 2.

Figure 6

Premature ventricular contraction burden reduction after bipolar ablation (n = 18).