Bipolar Ventricular Tachycardia (VT) Study
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|ClinicalTrials.gov 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 : March 19, 2019
|First Submitted Date ICMJE||February 23, 2015|
|First Posted Date ICMJE||February 27, 2015|
|Last Update Posted Date||March 19, 2019|
|Actual Study Start Date ICMJE||February 18, 2015|
|Estimated Primary Completion Date||December 2019 (Final data collection date for primary outcome measure)|
|Current Primary Outcome Measures ICMJE
||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||Complete list of historical versions of study NCT02374476 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE
|Original Secondary Outcome Measures ICMJE||Same as current|
|Current Other Pre-specified Outcome Measures||Not Provided|
|Original Other Pre-specified Outcome Measures||Not Provided|
|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.|
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 ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Suspended|
|Estimated Enrollment ICMJE
|Original Estimated Enrollment ICMJE
|Estimated Study Completion Date ICMJE||December 2020|
|Estimated Primary Completion Date||December 2019 (Final data collection date for primary outcome measure)|
|Eligibility Criteria ICMJE||
|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|
|NCT Number ICMJE||NCT02374476|
|Other Study ID Numbers ICMJE||GCO 14-1827|
|Has Data Monitoring Committee||Yes|
|U.S. FDA-regulated Product||
|IPD Sharing Statement ICMJE||
|Responsible Party||Srinivas Dukkipati, Icahn School of Medicine at Mount Sinai|
|Study Sponsor ICMJE||Srinivas Dukkipati|
|Collaborators ICMJE||Biosense Webster, Inc.|
|PRS Account||Icahn School of Medicine at Mount Sinai|
|Verification Date||March 2019|
ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP