Clinical Trials

Predictors of effective ablation lesion delivery in the human left ventricle are not established, particularly in scar. Impedance drop and electrogram (EGM) attenuation are potential surrogates to assess this. Read More on PubMed

Ablation Index (AI) is a multiparametric quality marker to assess the durability of radiofrequency (RF) lesions. The comparative effectiveness and safety of AI versus time-based energy dosing for ablation of ventricular arrhythmias are unknown. Read More on PubMed

Radiofrequency catheter ablation has become an established treatment for ventricular tachycardia. The exponential increase in procedures has provided further insights into mechanisms causing arrhythmias and identification of ablation targets with the development of new mapping strategies. Since the definition of criteria to identify myocardial dense scar, borderzone and normal myocardium, and the description of isolated late potentials, local abnormal ventricular activity and decrementing evoked potential mapping, substrate-guided ablation has progressively become the method of choice to guide procedures. Accordingly, a wide range of ablation strategies have been developed from scar homogenization to scar dechanneling or core isolation using increasingly complex and precise tools such as multipolar or omnipolar mapping catheters. Despite these advances long-term success rates for VT ablation have remained static and lower in nonischemic than ischemic heart disease because of the more patchy distribution of myocardial scar. Ablation aims to deliver an irreversible loss of cellular excitability by myocardial heating to a temperatures exceeding 50°C. Many indicators of ablation efficacy have been developed such as contact force, impedance drop, force-time integral and ablation index, mostly validated in atrial fibrillation ablation. In ventricular procedures there is limited data and ablation lesion parameters have been scarcely investigated. Since VT arrhythmia recurrence can be related to inadequate RF lesion formation, it seems reasonable to establish robust markers of ablation efficacy. Read More on PubMed

Radiofrequency catheter ablation (RFCA) represents an effective option for idiopathic premature ventricular contractions (PVCs) treatment. Ablation Index (AI) is a novel ablation marker incorporating RF power, contact force, and time of delivery into a single weighted formula. Data regarding AI-guided PVCs RFCA are currently lacking. Aim of the study was to compare AI-guided and standard RFCA outcomes in patients with PVCs originating from the right ventricle outflow tract (RVOT). Read More on PubMed

Background Catheter ablation for persistent atrial fibrillation (AF) is associated with less favorable outcomes than for paroxysmal AF. Substrate modification is often added to pulmonary vein isolation (PVI) to try to improve success rates. Recent studies have shown improved clinical outcomes with use of regional ablation index (AI) targets for PVI. We hypothesized that prospective use of AI-guided PVI in persistent AF patients would result in a low rate of PV reconnection at repeat electrophysiology study and that a high success rate can be achieved with durable PVI alone. Methods Forty consecutive patients with persistent AF underwent AI-guided PVI with target values of 550 for anterior and 400 for posterior left atrial regions, followed by a protocol-mandated repeat procedure after 2 months. Patients were monitored for atrial tachyarrhythmia recurrence via daily plus symptom-initiated ECG recordings for 12 months. Recurrence was defined as ≥30 seconds of any atrial tachyarrhythmia after a 3-month blanking period. Results PV reconnection was seen at repeat electrophysiology study in 22% of patients, affecting 7% of PVs. Ablation on the intervenous carina was required in 44% patients to achieve durable PVI. Atrial tachyarrhythmia recurrence was documented in 8 (20%) patients, only one of whom had PV reconnection at repeat study. At 12 months, 38/40 (95%) patients were in sinus rhythm, with 4 (10%) patients having started antiarrhythmic drugs. Higher body mass index and excess alcohol consumption were the only significant factors associated with atrial tachyarrhythmia recurrence. Conclusions Use of AI targets results in a high level of durable PVI. A good clinical outcome can be achieved in the great majority of persistent AF patients with AI-guided PVI alone. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT02628730. Read More on PubMed