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.

Improvement in Atrioventricular Conduction Using Cardioneuroablation Performed Immediately after Pulmonary Vein Isolation.

In patients with atrial fibrillation (AF) recurrences after pulmonary vein isolation (PVI), concomitant treatment using anti arrhythmic drugs (AADs) can lead to clinical success. However, patients with atrioventricular (AV) block may not be good candidates for concomitant AAD therapy due to the risk of further worsening of conduction abnormalities. Cardioneuroablation (CNA), as an adjunct to PVI, may offer a solution to this problem. We present a case of a 74-year-old male with paroxysmal AF and first degree AV block in whom CNA following PVI led to PR normalization. The presented case describes an example of CNA utilization in patients with AF undergoing PVI who have concomitant problems with AV conduction and shows that CNA can be sometimes useful in older patients with functional AV block.

Prognostic value of noninvasive programmed stimulation in primary prevention implantable cardioverter-defibrillator recipients.

Background: Implantable cardioverter-defibrillator (ICD) offers an opportunity to study inducibility of ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict future arrhythmic events or mortality in patients with primary prevention ICD, has not yet been examined. Methods: From the NIPS-ICD study (ClinicalTrials ID: NCT02373306) 41 consecutive patients (34 males, age 64 ± 11 years, 76% ischemic cardiomyopathy [ICM]) had ICD for primary prevention indication. Patients underwent NIPS using a standardized protocol of up to three premature extrastimuli at 600, 500 and 400 ms drive cycle lengths. NIPS was classified as positive if sustained VT or VF was induced. The study endpoint was occurrence of sustained VT/VF during the follow-up. Results: At baseline NIPS, VT/VF was induced in 8 (20%) ICM patients. During the 5-year follow-up, the VT/VF occurred in 7 (17%) patients, all with ICM. The difference between NIPS-inducible versus NIPS-noninducible patients regarding VT/VF occurrence did not meet statistical significance (38% vs. 12%, log rank test p = .11). After a 5-year follow-up, the mortality rate was significantly higher in patients who had VT/VF induced at NIPS versus no VT/VF at NIPS (38% vs. 12%, p = .043). The occurrence of a composite endpoint consisting of VT/VF recurrence or death in patients with ICM was also most frequent in the NIPS-inducible group (75% vs. 35%, p = .037). Conclusions: Inducibility of VT/VF during NIPS in ICM patients with primary prevention ICD is associated with higher mortality and higher incidence of composite endpoint consisting of death or VT/VF during a long-term observation.

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

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.

Catheter ablation of the cavotricuspid isthmus in patients with atrial flutter: predictors of long-term outcomes.

BACKGROUND: Predictors of long­term outcomes and an optimal catheter set for ablation of the cavotricuspid isthmus in patients with atrial flutter (AFL) are not well known. AIMS: This study aimed to identify predictors of clinical events following ablation. METHODS: We studied 741 patients (mean [SD] age, 62.2 [10.8] years; 248 women) who were followed for a mean (SD) time of 4.4 (2.7) years. The 2- versus 3­electrode approach and clinical predictors ofclinical events during follow­up were analyzed. RESULTS: The 2­electrode approach was faster (mean [SD] time, 62.5 [30.3] vs 101.4 [51] min; P <0.001), associated with shorter fluoroscopy time (13.1 [9.3] vs 20.3 [12.4] min; P < 0.001), cost­effective (8.29 [2.82] vs 11.89 [2.51] units; P <0.001), and more effective (92.1% vs 86.1%; P = 0.012). The independent predictors of AFL recurrence were: calcium blocker use (hazard ratio [HR], 3.24; 95% CI, 1.64-6.4), mitral valve disease (HR, 1.82; 95% CI, 1.12-2.95), previous stroke and/ or TIA (HR, 2.38; 95% CI, 1.21-4.65), pulmonary artery dilatation (HR, 3.94; 95% CI, 1.22-12.73), and previous pulmonary embolism (HR, 3.77; 95% CI, 1.14-12.43); of atrial fibrillation (AF): previous AF (HR, 6.054; 95% CI, 4.58-8), left atrial enlargement (HR, 1.43; 95% CI, 1.12-1.81), number of antiarrhythmic drugs used (HR, 1.16; 95% CI, 1.05-1.28), and mitral valve disease (HR, 1.28; 95% CI, 1.04-1.58); of pacemaker implantation: tachycardia­bradycardia syndrome (HR, 6.17; 95% CI, 3.16-12.05), previous second-/third­degree atrioventricular block (HR, 29.4; 95% CI, 7.37-117.28), centrally acting hypotensive drugs (HR, 29.55; 95% CI, 6.14-142.25), aortic dilatation or aneurysm (HR, 2.58; 95% CI, 1.06-6.3), a labile international normalized ratio (HR, 3.45; 95% CI, 1.72-6.93), left bundle branch block (HR, 4.7; 95% CI, 1.49-14.82), the shortest R­R interval during AFL (HR, 1.003; 95% CI, 1.001-1.005), previous cardiac surgery (HR, 2.69; 95% CI, 1.27-5.7), and aortic valve disease (HR, 2.22; 95% CI, 1.08-4.59). CONCLUSION: Ablation of cavotricuspid isthmus with a minimal number of electrodes is safe and effective. Specific predictors of clinical events during long­term follow-up can be determined.

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.

[Intracardiac echocardiography for optimisation of RF ablation for incessant idiopathic ventricular tachycardia originating from the aorto-mitralis continuity in a patient with tachycardia-induced cardiomyopathy]. / Echokardiografia wewnatrzsercowa w optymalizacji ablacji RF ustawicznego czestoskurczu komorowego z okolicy ciaglosci aortalno-mitralnej powodujacego rozwój kardiomiopatii tachyarytmicznej.

We describe a case of a 67-year-old woman with incessant idiopathic ventricular tachycardia and tachycardia-induced cardiomyopathy who underwent a successful RF ablation of the arrhythmic focus located in the aorto-mitral continuity. The optimal approach and titration of RF energy was achieved by means of the intracardiac echocardiography. The regression of signs of heart failure has been also observed.

Non-invasive programmed stimulation to identify high-risk patients with implanted cardioverter defibrillator (the NIPS-ICD study): study protocol for a randomized controlled trial.

BACKGROUND: The use of an implantable cardioverter defibrillator (ICD) is a widely used and effective therapy, which reduces the risk of cardiac death in many cardiac diseases, both implanted for secondary and primary prevention. However, recurrent arrhythmias and ICD discharges have adverse prognostic significance. Additional parameters that would identify patients who are at increased risk of arrhythmias and appropriate ICD interventions would be of clinical value. Modern ICDs are relatively complex devices with a number of functions, including the possibility to perform noninvasive programmed stimulation (NIPS) with an implanted electrode located in the right ventricle. METHODS/DESIGN: The aim of the study is to evaluate the usefulness of NIPS in determining the likelihood of life-threatening arrhythmic events in patients with ICD. The study will include 150 consecutive patients with an ICD implanted both for primary and secondary prevention, regardless of etiology, who are followed in the outpatient clinic of our center and do not meet the exclusion criteria. A 12-step St. George's Hospital NIPS protocol using ICD will be performed. The endpoint is to induce sustained ventricular arrhythmia (VT lasting more than 30 seconds or hemodynamically unstable VT/VF) or the end of the protocol. In case of serious and/or hemodynamically unstable heart rhythm disorders resistant to treatment with a low-energy antiarrhythmic pacing (ATP), the patient receives a short-term intravenous general anesthesia, and internal or external defibrillation is performed. Outpatient follow-up will be conducted during the pre-scheduled ICD control visits. An analysis of records of a registered memory device will be collected, a patient will be interviewed, and physical examination will be carried out. The follow-ups will be held every 3 months for 1 year. The primary endpoint of the follow-up will be appropriate intervention of ICD or sudden cardiac (arrhythmic) death; the secondary, appropriate ICD intervention, or death from cardiovascular causes; and the tertiary, appropriate ICD intervention, death or hospitalization for cardiovascular causes. DISCUSSION: It is expected that appropriate ICD interventions during follow-up will occur more often in patients who had sustained ventricular arrhythmias induced during NIPS. CLINICAL TRIALS REGISTRY: ClinicalTrials.gov, NCT02373306 , date of registration: 26 February 2015.

Dyspnoea related to pre-excitation during sinus rhythm as a new indication for catheter ablation.

BACKGROUND: Patients with pre-excitation without arrhythmic symptoms are diagnosed as Wolff-Parkinson-White (WPW) pattern. AIM: To evaluate the efficacy of radiofrequency ablation (RFA) in patients with a WPW pattern and reported dyspnoea. METHODS: Five patients (four adults and one adolescent, all female, age 33 ± 15 years) with a WPW pattern were referred due to dyspnoea and exercise intolerance. None had a history of paroxysmal syncope, pre-syncope, dizziness or palpitation. Before and after RFA, additional tests were used to exclude organic diseases of the pulmonary vessels, heart and lung, as well as bronchial hyperreactivity and metabolic diseases. Cardiopulmonary exercise test (CPET), echocardiography, time of forced expiration, baseline dyspnoea index (BDI), and transition dyspnoea index (TDI) were included into an objective evaluation of breath pattern. RESULTS: In all investigated patients, no arrhythmia was inducible during the electrophysiology study. The time of forced expiration increased immediately after RFA from 15.8 ± 2.9 to 29.2 ± 4.4 s (p < 0.001). The BDI score before RFA was 6.7 ± 1.9 and the TDI score after RFA showed a significant improvement: 8.0 ± 1.2 (p < 0.05). CPET revealed significant improvement in cardiopulmonary capacity after RFA in all cases: peak oxygen consumption [mL/kg/min]: 31.1 ± 7 vs. 42.6 ± 9.6 (p = 0.014); peak exercise minute ventilation [L/min]: 60.0 ± 19.9 vs. 82.0 ± 27 (p = 0.006); peak exercise tidal volume [L]: 1.56 ± 0.25 vs. 2.04 ± 0.24 (p = 0.002); ratio dead space/tidal volume at the end of exercise: 28 ± 2.6 vs. 25 ± 2.3 (p = 0.005). CONCLUSIONS: Dyspnoea during sinus rhythm in women with pre-excitation may be considered to be an evaluation criterion before RFA.