Ablation-Index Guided Ventricular Tachycardia Ablations

Ventricular Tachycardia Clinical Trial

Official title: Ablation-Index Guided Ventricular Tachycardia Ablation in Patients With Ischemic Cardiomyopathy - a Prospective, Multicenter Registry.

Status Not yet recruiting

Clinical Trial Summary

Over the last decade, radiofrequency catheter ablation (RFCA) has become an established treatment for ventricular arrhythmias (VA). Due to the challenging nature of visualizing lesion formation in real time and ensuring an effective transmural lesion, different surrogate measures of lesion quality have been used. The Ablation Index (AI) is a variable incorporating power delivery in its formula and combining it with CF and time in a weighted equation which aims at allowing for a more precise estimation of lesion depth and quality when ablating VAs. AI guidance has previously been shown to improve outcomes in atrial and ventricular ablation in patients with premature ventricular complexes (PVC). However research on outcomes following AI-guidance for VT ablation specifically in patients with structural disease and prior myocardial infarction remains sparse. We aim at conducting a prospective observational multicenter registry investigating the efficacy and safety of AI-guided VA ablation in patient with ischemic and non-ischemic cardiomyopathy.

Clinical Trial Description

Over the last decade, radiofrequency catheter ablation (RFCA) has become an established treatment for ventricular arrhythmias (VA). RFCA uses electromagnetic energy that transforms into heat upon delivery into the myocardium and irreversibly damages the viable myocytes, causing the loss of cellular excitability. Irreversible loss of cellular excitability generally occurs at temperatures exceeding 50°C, while at lower temperatures, the damage is not permanent and myocytes can recover excitability, leading to VA recurrences. Due to the challenging nature of visualizing lesion formation in real time and ensuring an effective transmural lesion, different surrogate measures of lesion quality have been used. The fall in local impedance during ablation has been considered as a first marker of the direct effect of ablation in cardiac tissue but the generator impedance drop does not correlate well with lesion size. First, large impedance drops can indicate impeding steam pop without effective lesion formation. Second scar tissue carries a lower impedance than healthy tissue due to their higher water/collagen content and make impedance drops less reliable.

One of the major determinants of lesion formation is an adequate contact between the tip of the catheter and the myocardial surface. A first major technological advancement in ablation catheters was the development of sensors at the distal tip capable of monitoring contact (contact force, CF). A recent ablation marker is the Force-Time-Integral (FTI), which multiplies CF by radiofrequency application duration. Limitations in this ablation parameter are the exclusion of maximal power settings being delivered and the assumption that a single target FTI is required in all myocardial segments with varying wall thickness and underlying substrate. Also for prolonged energy deliveries, the contribution of radiofrequency application duration is proportionally less important in lesion creation than CF1. To overcome some of these limitations, the Ablation Index (AI) was introduced. This is a variable incorporating power delivery in its formula and combining it with CF and time in a weighted equation. It has shown to be a more precise estimation of lesion depth and quality in animal models and humans1 than FTI, time alone or impedance drop.

AI guidance has previously been shown to improve outcomes in atrial and ventricular ablation in patients with premature ventricular complexes (PVC). However research on outcomes following AI-guidance for VT ablation specifically in patients with structural disease and prior myocardial infarction remains sparse, with mainly research conducted in ex-vivo porcine or canine models. In theory, use of AI to guide ablation in this subpopulation of VT patients may shorten procedure time and improve procedural safety in comparison to ablation guided by less reliable conventional parameters or fixed energy application durations. The available research assessing AI-guided VT ablations in patients with structural heart diseased focused on procedural parameters and did not deliver any clinically/prognostic relevant data.

While there has been a technological advancement in the monitoring and titration of energy delivered to yield effective RF lesion formation, the application of these tools have been scarcely investigated and implemented in the practice of VT ablation. Since VT recurrence in patients treated with RFCA can be related, at least partly, to inadequate RF lesion formation, it is imperative to continue to explore the need for robust, transferrable markers of ablation efficacy. Further, longer procedure time and time under general anesthesia during VT ablation procedures have been associated with higher procedural morbidity. Thus, a means of concurrently shortening procedure time while maintaining clinical effectiveness may together improve overall outcomes in patients with structural heart disease who undergo VT ablation. The present study will aim at clarifying the efficacy and safety of one of these markers of ablation efficacy, the ablation-index, in a large cohort of patients undergoing VA, thereby providing the first long-term registry on this particular ablation procedure. ;

Related Conditions & MeSH terms

• Arrhythmias, Cardiac
• Cardiomyopathies
• Tachycardia
• Tachycardia, Ventricular
• Ventricular Arrythmia
• Ventricular Tachycardia

• NCT number: NCT06051994
• Study type: Observational [Patient Registry]
• Source: Rush University Medical Center
• Contact: Henry D Huang, MD
• Phone: +1 312-942-5020
• Email: henry_d_huang@rush.edu
• Status: Not yet recruiting
• Start date: July 2024
• Completion date: November 2029