Acute and long-term results of bipolar radiofrequency catheter ablation of refractory ventricular arrhythmias of deep intramural origin

Abstract

BACKGROUND Successful bipolar radiofrequency catheter ablation (RFCA) of refractory ventricular arrhythmias (VAs) has been reported. However, the efficacy, safety, and long-term outcomes of bipolar RFCA of VAs are not fully determined.OBJECTIVE The purpose of this study was to evaluate the effectiveness and safety of bipolar RFCA in treating refractory VAs during long-term follow-up.METHODS Eighteen patients who underwent bipolar RFCA for ventricular tachycardia (VT) at 7 institutions were retrospectively investigated. Underlying heart diseases included remote myocardial infarction (n 5 3 [17%]) and nonischemic cardiomyopathy (n 5 15 [83%]). Although unipolar RFCA was performed in all patients, either it failed to suppress VT or VT recurred. The interventricular septum, left ventricular free wall, and left ventricular summit were targeted for bipolar RFCA.RESULTS Acute success (VT termination and/or noninducibility) was achieved with bipolar RFCA in 16 patients (89%). Complications during the procedure included complete atrioventricular block (n 52) and coronary artery stenosis (n 5 1). One patient underwent chemical ablation after bipolar RFCA failure. At 12-month followup, VT reoccurred in 8 patients (44%). However, in patients with recurrence, VT burden had decreased: only 4 patients underwent re-RFCA, and only 1 of the 4 required chemical ablation. In the remaining 4 patients, re-RFCA was not required, as VT was controlled by medication or an implantable cardioverter-defibrillator. CONCLUSION Bipolar RFCA is useful for acute suppression of refractory VT. Although VT recurrence rates during long-term followup were relatively high, we observed a significant reduction in VT burden.

Impedance decrement indexes for avoiding steam‐pop during bipolar radiofrequency ablation: An experimental study using a dual‐bath preparation

“…Because of the high current density between the two ablation catheters, BIP ablation can create deeper lesions as compared with UNIP ablation, and this has been proven both by experimental and clinical studies 3–5 . Indeed, several clinical studies reported that UNIP ablation refractory arrhythmias originating from deep inside the myocardium were successfully ablated following BIP ablation with excellent acute and long‐term outcomes 10,11 . Therefore, BIP ablation is considered an important therapeutic option in some patients but parameters for safely performing the BIP ablation have not been well studied.…”

“…However, in several studies, 9,15 these indexes were reported to be insufficient to prevent the occurrence of steam‐pop. Although steam‐pop‐related complications were rare in the clinical studies, 10,11 caution is required because experimental studies using a relatively high energy delivery showed a high incidence of steam‐pop during BIP ablation 16,17 …”

“…[3][4][5] Indeed, several clinical studies reported that UNIP ablation refractory arrhythmias originating from deep inside the myocardium were successfully ablated following BIP ablation with excellent acute and long-term outcomes. 10,11 Therefore, BIP ablation is considered an…”

“…6,7 However, in several studies, 9,15 these indexes were reported to be insufficient to prevent the occurrence of steam-pop. Although steam-pop-related complications were rare in the clinical studies, 10,11 caution is required because experimental studies using a relatively high energy delivery showed a high incidence of steam-pop during BIP ablation. 16,17 The results of this study were similar to the previous clinical and experimental reports on UNIP ablation, 6,7 ) with transmural lesion and without steam-pop, and closed triangle is RF applications (8 times) both with transmural lesion and steam-pop.…”

Specific electrogram characteristics impact substrate ablation target area in patients with scar‐related ventricular tachycardia—insights from automated ultrahigh‐density mapping

“…A possible reason is a more common midmyocardial or epimyocardial distribution of the often partly patchy substrate in nonischemic cardiomyopathy that might not be detected with an endocardial mapping approach 23,24 . A substrate of that kind might be more accessible through an epicardial or in some cases bipolar ablation approach 25 . Furthermore, depiction of the myocardial scar by magnetic resonance imaging or computed tomography might be helpful to identify the optimal ablation strategy 26 …”