Voltage mapping and pacing to assess the level of pulmonary venous isolation achieved with a novel circular multielectrode ablation catheter.

Aims The aim of the study was to determine the level of pulmonary vein (PV) isolation achieved with the use of a novel radiofrequency circular multielectrode ablation catheter [pulmonary vein ablation catheter (PVAC)] in patients with paroxysmal atrial fibrillation. Although some efficacy data have been presented, the level of PV isolation, which is crucial both for efficacy and safety of the ablation, has not been defined with this new ablation catheter. Methods and results Detailed sinus rhythm voltage maps using an electroanatomic mapping system and projected on 3D computed tomography-derived reconstructions of the left atrium (LA) were obtained before and after PV isolation with the PVAC. Left atrium–PV entry and exit block was assessed for each vein. The population consisted of 12 patients, mean age 57 ± 6 years, seven male. After ablation, an extensive zone of potential reduction that included the ostium of each PV was observed in all patients. Bipolar voltages were significantly reduced in all PVs and in the LA close to the vein ostia, the mean voltage reduction was >80%. Conclusion Using the PVAC, (i) PVs are isolated at the level of the PV ostium and, importantly, outside the tubular portion and (ii) significant voltage reduction is also recorded at various extent proximal to the PV ostium at the level of the antral region

Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms:results from a multicentre long-term registry

AIMS : To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs). METHODS AND RESULTS: Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03]. CONCLUSION : Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences