Intramural Needle Ablation for the Treatment of Refractory Ventricular Arrhythmias

This study will examine the safety and efficacy of intramural needle ablation (INA) in the treatment of intramural ventricular arrhythmias in patients for whom standard RF ablation has been unsuccessful. The clinical team hypothesize that the increased current density and improved rates of transmural lesion creation seen with intramural needle ablation will lead to successful arrhythmia termination with minimal or no increased risk of complication.

Study Overview

• Status: Completed
• Conditions: Ventricular Arrythmia
• Intervention / Treatment: Device: Intramural Needle Ablation; Procedure: Ablation

Detailed Description

Radiofrequency (RF) ablation is the most commonly employed method for the catheter treatment of cardiac arrhythmias. Myocardial scar serves as the most frequent substrate for the genesis of both atrial and ventricular arrhythmias. Such scar frequently contains surviving myocyte bundles interspersed with fibrotic tissue, which leads to slow conduction. Areas of denser fibrosis cause conduction block. When appropriately arranged, conduction through or around these scars leads to the creation of a "reentry" circuit through which an arrhythmia is generated and maintained. Each reentry circuit contains within it an area called the isthmus, a portion of the circuit located in a position intimately related to the scar border zone. Electrical activation travels slowly through the isthmus before breaking out into normal myocardium. Ablation at the site of an isthmus will terminate a reentrant tachycardia.

A variety of techniques, including electroanatomic mapping and activation, entrainment, and substrate mapping, are employed during electrophysiologic (EP) study to identify areas of myocardial scar and potential isthmus sites. Points or lines of ablation using RF energy are then created in an attempt to interrupt the reentry circuit. Typically, RF energy is applied via a catheter tip electrode to the endocardial or epicardial surface of the heart and grounded via an electrode pad placed on the patient's skin. RF energy in this setting is dispersed through the entirety of the tissue between catheter tip and grounding pad. The standard 7-French, 4-mm tip catheters are highly successful at ablating circuits located within a few millimeters of the catheter tip. A focal, 1mm area of resistive heating occurs within the myocardium immediately in contact with the catheter tip; myocardial cell death occurs several millimeters more deeply through passive, conductive heating, which spreads outward from the contact point.

While the standard catheter is effective at the ablation of superficial arrhythmias, it has proven more problematic when used for deep myocardial sites or for creating transmural lesions. A number of alternatives have been developed in an attempt to access these sites. 8-mm or 10-mm catheter tips are able to create larger zones of resistive heating, delivering direct RF energy to a larger area of myocardium. A larger interface between catheter tip and blood improves cooling and allows for the delivery of more power without a rise in impedance.The clinical use of these larger catheters can, however, be limited by rapid temperature rises at the catheter-tissue interface, resulting in thrombus formation, char, and "steam pop" rupture of the endocardial surface. The use of irrigated ablation catheters have improved upon the ability to deliver RF energy without a sustained rise in impedance. Both open irrigated- and closed-loop irrigated catheters circulate saline along the catheter tip-myocardial interface, allowing for continued delivery of RF current without thrombus formation at the endocardial surface. Intramyocardial temperature rises accordingly without a concomitant endocardial temperature surge, creating larger and deeper myocardial ablation zones. Transcoronary ethanol ablation has also been employed with moderate success in patients with arrhythmias resistant to endocardial catheter ablation.This technology, however, grants only limited control over the size of the resulting infarct and is restricted by the need for perfusion of the scar zone by an accessible coronary artery.

Nevertheless, there remain occasions in which an arrhythmia cannot be eliminated by standard ablation techniques. This is seen most frequently due to deep intramural ventricular tachycardia, sometimes encountered following myocardial infarction. Both standard and alternative ablation strategies are frequently either unavailable or inadequate for termination of these arrhythmias.

Initial experience with an electrically active needle electrode have demonstrated that radiofrequency ablative energy can effectively create lesions of homogeneous necrosis. Needle electrodes have been used experimentally from the epicardial surface, from the endocardium ex vivo and in vivo in an internally irrigated form. It has been shown that the use of a narrow-gauge non-irrigated endocardial needle ablation catheter creates very narrow but deep lesions due to the small electrode size. Catheters featuring a retractable needle tipped electrode with intramyocardial saline infusion have also shown promise as a means of accessing deep myocardial circuits in ventricular tachycardia ablation.18

The proposed study will further examine the role of INA in patients with ventricular arrhythmias resistant to standard ablation techniques.

• Study Type: Interventional
• Enrollment (Actual): 52
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • New York
    • New York, New York, United States, 10029
      • Icahn School of Medicine at Mount Sinai

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 11 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• The study will include patients with any of the following criteria: a) monomorphic ventricular tachycardia (VT); b) frequent ventricular arrhythmia (defined as unifocal PVCs, couplets, non-sustained VT) with a PVC burden ≥13%, or is causing a decline in left ventricular (LV) ejection fraction to <40%; or c) previous failed ablation for one or more of the criteria above.
• ≥ 15 years of age.
• Left ventricular (LV) ejection fraction > 10% as estimated by echocardiography, contrast ventriculography or radionuclide imaging within the past 90 days.
• Clinical indication for catheter ablation of VT
• Intramural ventricular arrhythmias not terminable with standard ablation once enrolled in the Intramural Needle Ablation study or previous failed ablation within 6 months prior to enrollment.
• Ability to understand the requirements of the study and sign the informed consent form.
• Able and willing to comply with all pre-, post-, and follow-up testing and requirements.
• Projected lifespan greater than 1 year.

Exclusion Criteria:

• History of MI or CABG within 6 weeks.
• NYHA Class IV CHF.
• Patients with idiopathic ventricular arrhythmias defined as VT or PVCs that occur without evidence of structural heart disease and that are not causing significant depression of LV function.
• Women known to be pregnant or to have positive beta-HCG.
• Definite protruding left ventricular thrombus on pre-ablation echocardiography or other imaging modalities.
• Contraindication to heparin
• Allergy to radiographic contrast dye.
• Unstable angina that is not due to frequent or incessant VT.
• Acute non-cardiovascular illness or systemic infection.
• Thrombocytopenia (platelet count < 50,000 mm3) or coagulopathy.
• Cardiogenic shock unless it is due to incessant VT.
• Unable to sign consent.
• Projected lifespan of < 1 year.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intramural Needle Ablation	Device: Intramural Needle Ablation; The needle-tipped ablation catheter that will be used for the IN ablation uses radiofrequency like a standard RF ablation catheter, but delivers energy through an extendable/retractable needle.; Procedure: Ablation; standard ablation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants Who Had Freedom From Ventricular Arrhythmia at 6 Months	Number of participants with VT and number of participants with PVCs who had freedom from ventricular arrhythmia at 6 months for participants who had ablation performed using the experimental Needle ablation catheter versus standard ablation catheter. Needle - patient had ablation performed using the experimental Needle ablation catheter. Registry - patient had ablation using a standard ablation catheter and did not need additional ablation using the Needle catheter.	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Events of Procedural Complications	Number of events of procedural complications	at 6 months
Number of Participants With Post-ablation Inducibility		Day 1
Time to Termination		Day 1
Total Duration of Intramural Needle Ablation	Total duration of intramural needle ablation for patient who had ablation performed using the experimental Needle ablation catheter.	Day 1
Total Number of Intramural Needle Ablations	Total Number of Intramural Needle Ablations for patient had ablation performed using the experimental Needle ablation catheter.	Day 1
All-cause Mortality		at 6 months

Collaborators and Investigators

• Sponsor: Vivek Reddy
• Collaborators: Biosense Webster, Inc.

Publications and helpful links

General Publications

• Dukkipati SR, Nakamura T, Nakajima I, Oates C, Narui R, Tanigawa S, Sljapic T, Whang W, Koruth JS, Choudry S, Schaeffer B, Fujii A, Tedrow UB, Sapp JL, Stevenson WG, Reddy VY. Intramural Needle Ablation for Refractory Premature Ventricular Contractions. Circ Arrhythm Electrophysiol. 2022 May;15(5):e010020. doi: 10.1161/CIRCEP.121.010020. Epub 2022 Apr 27.

Study record dates

Study Major Dates

• Study Start (Actual): October 17, 2017
• Primary Completion (Actual): April 20, 2021
• Study Completion (Actual): April 20, 2021

Study Registration Dates

• First Submitted: June 28, 2017
• First Submitted That Met QC Criteria: June 28, 2017
• First Posted (Actual): July 2, 2017

Study Record Updates

• Last Update Posted (Actual): October 12, 2021
• Last Update Submitted That Met QC Criteria: September 14, 2021
• Last Verified: September 1, 2021

More Information

Terms related to this study

• Keywords: ventricular arrhythmia; intramural needle ablation
• Additional Relevant MeSH Terms: Pathologic Processes; Heart Diseases; Cardiovascular Diseases; Arrhythmias, Cardiac
• Other Study ID Numbers: GCO 17-1899

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes