Bipolar ablation of refractory atrial and ventricular arrhythmias: Importance of temperature values of intracardiac return electrodes.

INTRODUCTION: Bipolar radiofrequency catheter ablation (Bi-RFCA) emerged as an option for treatment of arrhythmias resistant to the conventional approach. Data on safety issues of Bi-RFCA, including temperature values of intracardiac return electrode (IRE) are lacking. OBJECTIVE: To determine the safety profile of Bi-RFCA regarding temperature measurements obtained from nonirrigated IRE of different sizes. METHODS: The study group consisted of consecutive patients after failed conventional RFCA who underwent Bi-RFCA. RESULTS: Out of 1510 RFCA performed in our center, 19 patients underwent Bi-RFCA due to refractory to previous RFCA ventricular arrhythmias (15 patients) or typical atrial flutter (four patients). Nonirrigated small (4 mm) and large (8 mm) tip catheters were used as IRE in 14 (including three cross-overs to 8 mm IRE) and five patients, respectively. A total number of 164 bipolar applications were performed (128 for 4 mm and 36 for 8 mm IRE). Maximal temperatures of 4 mm IRE were significantly higher than those of 8 mm IRE (63°C ± 16°C vs 43°C ± 4°C; P = .027). A significant rise of temperature and steam-pops, preventing further Bi-RFCA, occurred in seven patients treated with 4 mm IRE. Bi-RFCA using 4 mm IRE operated at significantly higher impedance values (211 ± 83 vs 143 ± 38; P = .04) and lower power values (mean 20 W ± 6 W vs 32 W ± 7 W, P = .0005; max 29 W ± 9 W vs 39 W ± 10 W, P = .027). CONCLUSION: The use of 8 mm IRE for Bi-RFCA is associated with lower temperatures of the catheter used as ground and lower incidence of steam-pops which may suggest a better safety profile than 4 mm IRE. Determination of safety/efficacy balance requires further studies.

Right atrial position of a return electrode for bipolar ablation of the left posterosuperior process ventricular tachycardia.

INTRODUCTION: Radiofrequency (RF) catheter ablation (RFCA) of ventricular tachycardia (VT) is an effective method of treatment. However, when arrhythmia has ischemic etiology and originates from the posterosuperior process (PSP) of the left ventricular (LV) base, ablation performed with conventional unipolar energy sources may be challenging or impossible. METHOD AND RESULT: A 67-year-old male after six unsuccessful RFCA for highly symptomatic VT originating from PSP of LV base underwent successful RFCA using multiple bipolar RF applications delivered between two electrodes located at LV endocardium and adjacent right atrial sites. CONCLUSION: This case report shows that bipolar RFCA can be used for safe and successful treatment of VT originating from deep PSP of LV base.

Prognostic value of noninvasive programmed stimulation in patients with implantable cardioverter defibrillator.

BACKGROUND: Implantable cardioverter defibrillator (ICD) offers an opportunity to examine vulnerability to ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict VT/VF recurrences has not yet been established. PURPOSE: To examine the predictive value of NIPS for identification of patients with VT/VF recurrences. METHODS: The study group consisted of consecutive 105 ICD recipients included in the prospective NIPS-ICD study (ClinicalTrials ID: NCT02373306) (88 males, age 65 ± 11 years). The patients underwent NIPS using the protocol up to three premature extrastimuli at 600-500- and 400-ms drive cycle lengths. The endpoint of NIPS was induction of sustained VT or VF or completion of the protocol. RESULTS: VT/VF was induced in 29 (27.6%) patients. During a 12-month follow-up NIPS-inducible patients had significantly more frequently appropriate ICD therapy than noninducible patients (17% vs 4%, P = 0.023). NIPS-induced VT/VF had a sensitivity of 63%, specificity of 75%, positive predictive value of 17%, and negative predictive value of 96% for identification of patients with future VT/VF. Apart from NIPS, age ≥ 65 years, QRS duration, treatment with angiotensin-converting enzyme, history of coronary artery bypass grafting, history of VT/VF prior to NIPS, and prior appropriate ICD therapy were also associated with VT/VF recurrences. Multivariate analysis showed that, together with QRS duration, NIPS result was an independent predictor of future VT/VF. Predictive value of NIPS was significantly higher in ischemic than nonischemic patients. CONCLUSIONS: NIPS result is associated with future VT/VF. Noninducibility at NIPS identifies those patients with high accuracy who will have uneventful follow-up.

Ultrasound­guided venous access facilitated by the Valsalva maneuver during invasive electrophysiological procedures.

BACKGROUND: Data on the feasibility of an ultrasound­guided venous access (USGVA) for catheter ablation (CA) and electrophysiological studies (EPS) in large cohorts are scarce. The impact of the Valsalva maneuver (VM), which can increase the diameter of the femoral vein (FV), on the USGVA is unknown. AIMS: The study aimed to determine the impact of the VM on FV diameters during establishing the USGVA and overall safety and effectiveness profile of the USGVA in a large cohort. METHODS: Consecutive patients undergoing CA and/ or EPS with the USGVA were included, and those with anatomical landmark­guided VA were recruited as controls. In a subgroup of USGVA patients, a VM­facilitated FV puncture was performed. The measurements obtained before and during the VM were used to calculate the estimated access area (EAA) of the FV RESULTS: A total of 1564 ultrasound-guided FV accesses in 876 patients and 172 FV accesses in 105 patients in the anatomical­VA group were performed. We observed no major complications associated with the USGVA. Minor adverse events related with VA were less common in the USGVA group than in controls (1.5% vs 6.7%, respectively; P = 0.001), resulting in a 4­fold decrease in VA­related complications. In 204 consecutive patients who underwent the VM­facilitated USGVA, the FV diameters increased during VM in both vertical (mean [SD], 10.1 [3] mm vs 14.4 [3.2] mm; P <0.001) and horizontal axes (10.6 [2.9] mm vs 14.5 [3.2] mm; P <0.001). This led to the mean (SD) increase in EAA of 38%: from 0.8 (0.2)cm2 at baseline to 1.1 (0.2) cm2 during VM (P <0.001). CONCLUSIONS: The USGVA for EPS and/ or CA is feasible. Complication rates for the USGVA are low and result in minor events. The Valsalva maneuver is a simple way to remarkably increase the femoral vein EAA and it can be helpful in performing the USGVA in difficult cases.

Bipolar radiofrequency ablation delivered from coronary veins and adjacent endocardium for treatment of refractory left ventricular summit arrhythmias.

BACKGROUND: Radiofrequency catheter ablation (RFCA) of premature ventricular complexes (PVC) and ventricular tachycardia (VT) can be an effective method of treatment. However, when arrhythmia originates from the left ventricular summit (LVS), an ablation performed with conventional unipolar energy sources can be challenging and may require alternative approaches. Bipolar RFCA from coronary veins and an adjacent endocardium in cases of refractory PVC/VT has not yet been studied. METHODS: We retrospectively analysed cases of consecutive patients who underwent bipolar ablation in whom conventional unipolar ablation of LVS PVC/VT and antiarrhythmic drugs failed to abolish arrhythmia. Bipolar RFCA was delivered from the earliest PVC/VT activation located in the coronary venous circulation and opposite LV endocardial sites. RESULTS: A total number of 4 patients (1 female, age 55 ± 10 years) underwent bipolar ablation of LVS from coronary veins and an adjacent endocardium. Bipolar RFCA led to acute elimination of PVC/VT in all patients. A mean bipolar RFCA time was 244 ± 15 s. There were no complications during procedures and all antiarrhythmic drugs were discontinued. A follow-up lasted 15 ± 4 months; there was no VT recurrence and the mean 83 ± 27 % PVC burden reduction (24250 ± 1372 vs. 3000 ± 3600 PVC/d; p = 0.0228) was achieved. All patients remained symptom-free. CONCLUSIONS: Bipolar RFCA from coronary veins and an opposite endocardium can be used for safe and successful treatment of PVC/VT originating from a deep LV summit.

Anatomic approach with bipolar ablation between the left pulmonic cusp and left ventricular outflow tract for left ventricular summit arrhythmias.

BACKGROUND: Radiofrequency catheter ablation (RFCA) of ventricular arrhythmias (VAs) arising from the inaccessible basal region of the left ventricular summit (LVS) is challenging due to proximity to coronary vessels, epicardial fat, and poor radiofrequency (RF) delivery within the distal coronary venous system. OBJECTIVE: The purpose of this study was to describe the outcomes of an anatomic approach to inaccessible LVS-VAs using bipolar radiofrequency (Bi-RFCA) delivered from the anatomically adjacent left pulmonic cusp (LPC) to the opposite left ventricular outflow tract (LVOT). METHODS: Patients from 3 centers who had undergone Bi-RFCA for inaccessible LVS-VAs refractory to conventional RFCA using an anatomic approach targeting the adjacent LPC (reversed U approach) with catheter tip pointing inferiorly within the LPC and LVOT were reviewed. RESULTS: Seven patients (age 59 ± 12 years; 3 women) underwent Bi-RF from the LPC to the LVOT for LVS-VAs after ≥1 failed conventional RFCA. Bi-RFCA (power 36 ± 7 W; duration 333 ± 107 seconds) resulted in VA suppression in 5 of 7 patients. In 2 cases, Bi-RFCA was successfully performed using dextrose 5% in water. No complications occurred. After mean follow-up of 14 ± 6 months, no recurrent VT was documented in 2 of 2 patients with baseline VT. Mean 84% reduction in premature ventricular contraction (PVC) burden (31% ± 13% vs 4% ± 5% PVCs per day; P = .0027) was documented in the other patients. CONCLUSION: In patients with LVS-VAs arising from the inaccessible region and refractory to conventional RFCA, an anatomic approach using Bi-RFCA from the LPC and opposite LVOT is an effective alternative approach.