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Bipolar Ventricular Tachycardia (VT) Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02374476
Recruitment Status : Suspended (DMC recommended enrollment halt due to a higher proportion anticipated SAEs in intervention group vs registry group.)
First Posted : February 27, 2015
Last Update Posted : January 30, 2020
Biosense Webster, Inc.
Information provided by (Responsible Party):
Srinivas Dukkipati, Icahn School of Medicine at Mount Sinai

Tracking Information
First Submitted Date  ICMJE February 23, 2015
First Posted Date  ICMJE February 27, 2015
Last Update Posted Date January 30, 2020
Actual Study Start Date  ICMJE February 18, 2015
Estimated Primary Completion Date April 1, 2020   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: February 23, 2015)
Freedom from recurrent VT [ Time Frame: 6 months ]
Freedom from recurrent VT at 6 months, defined as sustained ventricular tachycardia lasting longer than 30 seconds and identified due to clinical symptoms or during device interrogation.
Original Primary Outcome Measures  ICMJE Same as current
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: February 23, 2015)
  • Procedural complications [ Time Frame: 6 months ]
    Incidence of procedural complications which includes death, stroke, MI, heart failure, conduction abnormalities, pericardial effusion requiring drainage, hematoma, pseudoaneurysm
  • Post-ablation inducibility [ Time Frame: 6 months ]
    Incidence of the induction of any sustained arrhythmia post-ablation, with a duration > 15 seconds of MMVT. Post ablation inducibility is measured via program stimulation.
  • Time to termination [ Time Frame: 6 months ]
  • Total duration of bipolar ablation [ Time Frame: 6 months ]
  • All cause mortality [ Time Frame: 6 months ]
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title  ICMJE Bipolar Ventricular Tachycardia (VT) Study
Official Title  ICMJE Bipolar Catheter Ablation for the Treatment of Refractory Scar-Related Ventricular Arrhythmia
Brief Summary This non-randomized study will examine the safety and efficacy of irrigated bipolar radiofrequency (RF) ablation in the treatment of ventricular tachycardia (VT) in patients for whom standard VT unipolar RF ablation has been unsuccessful. VT is a serious abnormality of the heart's electrical system. Ablation is a procedure that cauterizes heart tissue using catheters (long tubes that can be moved within or along the outside of the heart). Cauterizing the heart tissue is accomplished by using heat to damage the abnormal heart tissue that is not working well so that it can stop affecting the rest of the heart. Usually, heat is delivered using a unipolar catheter, in which energy travels from the catheter tip to a grounding pad. This research study seeks to find out if a bipolar ablation catheter, in which the energy travels between two catheter tips on either side of the heart muscle, can be used to eliminate the arrhythmia when the unipolar ablation is unsuccessful. The hypothesis is that the increased current density and improved rates of transmural lesion creation seen with bipolar RF ablation will lead to successful arrhythmia termination with minimal or no increased risk of complication.
Detailed Description

STUDY OBJECTIVE This study will examine the role of irrigated bipolar radiofrequency (RF) ablation for the treatment of intramural ventricular tachycardia in patients who have failed standard unipolar RF ablation. The hypothesis is that the increased current density and improved rates of transmural lesion creation seen with bipolar RF ablation will lead to successful arrhythmia termination with minimal or no increased risk of complication.

INTRODUCTION, RATIONALE 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 arrhythmia. 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, unipolar 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 impedence. 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. 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, but are not currently available in the US. 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 unipolar ablation technique. 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.

Recently, several centers have employed irrigated bipolar ablation (BA) to target arrhythmias not amenable to unipolar ablation. During BA, two catheters are connected to either pole of an RF generator, allowing either catheter to function as the "active" catheter and the other the "return" catheter. Rather than being dispersed between the catheter tip and a distant grounding pad, BA concentrates energy between two catheter tips positioned on opposing sides of a target scar. BA may thus improve lesion transmurality through synergistic, simultaneous heating and increased current density leading to concentrated thermal injury.

Initial experience in the use of BA technology in mammalian hearts demonstrated that it could successfully be applied to create discrete areas of myocardial necrosis with minimal risk of complication. When compared to unipolar ablation, several studies suggested that BA could create larger areas of necrosis and transmural lesions with only rare episodes of perforation. Subsequent experience in human hearts was predominantly surgical: a large number of observational studies and reviews demonstrated the effectiveness and safety of BA in patients undergoing pulmonary vein isolation and Cox-Maze surgery as either isolated procedures or as adjuncts to valve replacement or coronary artery bypass surgery.

Despite its broad use during surgical ablation, the application of BA during catheter-based therapies is limited. Recently, our group demonstrated the utility of BA in both an in vitro model and in a series of patients with arrhythmia resistant to unipolar ablation. When compared to unipolar RF ablation, BA was found to be more likely to achieve transmural lesions in a porcine heart model (33% vs 82%, respectively, p = 0.001) and could do so in tissue up to 25 mm thickness. Clinically, all septal atrial flutters, 5 of 6 septal VTs, and 2 of 4 free-wall VTs were successfully acutely terminated.

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

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Condition  ICMJE Ventricular Tachycardia
Intervention  ICMJE Device: Bipolar Ablation
Patients will undergo bipolar ablation if unipolar ablation unsuccessful
Study Arms  ICMJE Experimental: Bipolar Ablation
All patients who meet inclusion criteria and have VT not terminable with unipolar ablation will undergo bipolar ablation.
Intervention: Device: Bipolar Ablation
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status  ICMJE Suspended
Estimated Enrollment  ICMJE
 (submitted: June 29, 2016)
Original Estimated Enrollment  ICMJE
 (submitted: February 23, 2015)
Estimated Study Completion Date  ICMJE June 1, 2020
Estimated Primary Completion Date April 1, 2020   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • ≥ 18 years of age.
  • The study will include all forms of scar VT--both ischemic (post-myocardial infarction) and non-ischemic (eg sarcoid, amyloid, dilated)--as determined by cardiac MRI and/or voltage mapping at the time of VT ablation.
  • Intramural VT not terminable with unipolar ablation once enrolled in the Bipolar study or previous failed unipolar ablation within 6 months prior to enrollment.
  • Ability to understand the requirements of the study and sign the informed consent form.
  • Willingness to adhere to study restrictions and comply with all post- procedural follow-up requirements
  • Projected lifespan greater than 1 year.

Exclusion Criteria:

  • Tissue Thickness less than 5 mm as assessed by electroanatomic mapping, CT, or MRI.
  • MI or CABG within 6 weeks.
  • NYHA Class IV CHF.
  • Women known to be pregnant or to have positive beta-HCG.
  • Participation in another study that would interfere with this study.
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE No
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE United States
Removed Location Countries Czech Republic,   Czechia
Administrative Information
NCT Number  ICMJE NCT02374476
Other Study ID Numbers  ICMJE GCO 14-1827
Has Data Monitoring Committee Yes
U.S. FDA-regulated Product
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
IPD Sharing Statement  ICMJE
Plan to Share IPD: No
Responsible Party Srinivas Dukkipati, Icahn School of Medicine at Mount Sinai
Study Sponsor  ICMJE Srinivas Dukkipati
Collaborators  ICMJE Biosense Webster, Inc.
Investigators  ICMJE
Principal Investigator: Srinivas Dukkipati, MD Icahn School of Medicine at Mount Sinai
PRS Account Icahn School of Medicine at Mount Sinai
Verification Date January 2020

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP