Ventricular TachycardiaSLO-VTNCT06464315
Functional Substrate-Only Guided VT Ablation
A study testing Functional Substrate-Only Mapping without VT Induction and Standard-of-Care Mapping/Imaging in people with Ventricular Tachycardia and Sudden Cardiac Death, run by VA Office of Research and Development at 1 site in United States.
Trial summary
Ventricular tachycardia (VT) is a leading cause of death and suffering in the Veteran population. Currently, ablation procedures are performed to destroy the diseased tissue that causes this problem. Read more about this study
- Who is it for?
- Ages 18 to 90 years
- Conditions the study is for
- Ventricular Tachycardia, Sudden Cardiac Death
- What is being tested?
- Functional Substrate-Only Mapping without VT Induction and Standard-of-Care Mapping/Imaging
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 36 participants
- Where
- 1 siteUnited States
- Study dates
- 18 Mar 2026to 1 Apr 2030
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 90 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Men and women >18 years of age referred for clinically indicated VT ablation and experience monomorphic or polymorphic scar-based VT documented by telemetry, ICD interrogation, ECG or event monitoring.
- Scar-based VT is defined as VT in patients with structural heart disease (assessed with either abnormal nuclear perfusion imaging (>5% defect), late gadolinium uptake on cardiac MRI, wall thinning <10mm or calcified myocardium on cardiac CT, akinesis or hypokinesis on echocardiogram, presence of Q waves on ECG, history of myocardial infarct).
- Patients undergoing epicardial VT ablation and who undergo prophylactic percutaneous hemodynamic support devices will also be included.
Who cannot join
- Patients without structural heart disease will be excluded from the pri-mary analysis, but enrolled in a prospective registry
- Patients who are pregnant
- Presence of intracardiac thrombus
- active acute coronary ischemia with unrevascularized coronary artery disease (CAD >70% stenosis)
- Active bacteremia
- Inaccessible ventricles due to dual mechanical valves
- Inability to tolerate and inability to tolerate anticoagulation during ablation and for at least 1 month after ablation
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
VA San Diego Healthcare System, San Diego, CA
San Diego, California, 92161-0002
About this study
Official title: Functional Substrate-Only Mapping Technique to Guide Ablation of Arrhythmogenic Substrate Underlying Ventricular Tachycardia
Ventricular tachycardia (VT) is a leading cause of death and suffering in the Veteran population. Currently, ablation procedures are performed to destroy the diseased tissue that causes this problem. This study will test to see if an experimental strategy of only targeting regions of slow conduction without the induction of VT can improve the efficacy and safety of VT ablation. Once this study is completed, the investigators will know whether this ablation strategy could help increase the efficacy, safety and efficiency of ablation therapy of fatal heart rhythms.
Read the detailed description
Ventricular tachycardia (VT) remains a leading cause of death and morbidity in the veteran population, but current ablation procedures to treat VT are limited by hemodynamic instability of induced VT during standard invasive activation mapping (up to 80% of induced VT), lengthy ablation procedures (~8 hours), and difficulty in accurately localizing the critical origination sites of VT. The long-term goal is to simplify VT ablation using invasive functional substrate mapping techniques to improve the safety, efficacy, and efficiency of VT catheter ablation. The overall objectives in this application are to i) perform a randomized clinical trial to test whether performing simplified VT ablation guided only by invasive functional substrate mapping without VT induction improves the safety and efficiency of VT ablation while maintaining similar efficacy compared to standard ablation and ii) mechanistically correlate abnormal functional substrate with VT origination sites localized using gold standard invasive activation mapping. The central hypothesis is that ablation of slowly conducting tissue characterized by high frequency signals is sufficient to eliminate VT and improves clinical outcomes of VT ablation. The rationale is that recently developed sophisticated techniques to characterize functionally abnormal tissue can localize critical VT-sustaining substrate without needing to subjecting patients to mapping of hemodynamically unstable VT which is routinely done during standard of care ablation. The central hypothesis will be tested by pursuing one primary specific aim: Perform a randomized clinical trial to determine whether VT ablation guided only by invasive functional substrate mapping without VT induction decreases procedure time, fluoroscopy time, and procedural complications while maintaining similar efficacy compared to standard VT ablation controls. This study also includes 2 sub-aims to uncover VT mechanisms characterizing the distance of slowly conducting tissue to VT exit sites and provide a method to unmask critical arrhythmogenic substrate in non-ischemic cardiomyopathy patients in whom scar is not easily identified. The research proposed is innovative because it tests a novel strategy using new algorithms that can identify the critical tissue sustaining VT without requiring the induction of VT. The proposed research is significant because a functional substrate-guided only approach to VT ablation while still localizing the critical tissue causing VT is expected to increase the safety, efficacy, and efficiency of treating a fatal heart rhythm disorder
- Conditions
- Ventricular Tachycardia, Sudden Cardiac Death
- Being tested
- Functional Substrate-Only Mapping without VT Induction, Standard-of-Care Mapping/Imaging
- Keywords
- functional substrate mapping, conduction slowing, isochronal late activation mapping (ILAM), peak frequency signal analysis, deceleration zones
- Medical subject headings
- Tachycardia, Ventricular, Death, Sudden, Cardiac
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Functional Substrate-Only Mapping without VT InductionProcedure or surgery
Also called Isochronal late activation mapping (ILAM), peak frequency analysis
In this arm, invasive maps will be constructed by annotating the latest deflection and peak frequency during voltage mapping of stable intrinsic rhythm to localize areas of slow conduction. Annotated algorithms are cleared by the FDA. No VT will be purposefully induced in this experimental arm.
Standard-of-Care Mapping/ImagingProcedure or surgery
Conventional invasive scar (voltage) and electrical VT (entrainment, activation, pace) mapping will be used to guide VT ablation. Functional substrate mapping will not be used in this arm. VT will be induced using standard protocols.
| Study group | Role | What they receive |
|---|---|---|
| Functional substrate mapping only without VT induction | Experimental | In this experimental arm, only functional substrate mapping will be used to guide ablation of conduction slowing regions, without VT induction or mapping during VT. Ablation targets of conduction slowing will be identified as: 1) deceleration zones of conduction slowing, previously defined as 3 isochrones coalescing within 1cm radius. 2) wavefront discontinuities represented by lines of conduction block, previously defined as late potentials with at least 20ms of isoelectric segment, and 3) regions of slow conduction characterized by high peak frequency (220-500Hz), which uses spectral frequency analysis to identify signals with highest frequency as a surrogate for slow conduction. All regions exhibiting any of these 3 surrogates of slow conduction will be ablated. Receives: Procedure: Functional Substrate-Only Mapping without VT Induction |
| Standard VT Mapping | Active comparator | Standard-of-care mapping, including voltage mapping of intrinsic rhythm, entrainment, activation, and/or pace mapping, will be performed to guide VT ablation. Standard VT induction protocols will be performed. Receives: Procedure: Standard-of-Care Mapping/Imaging |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to composite endpoint (VT recurrence, death, or acute hemodynamic decompensation)
Ventricular arrhythmia recurrence is defined by an episode of sustained VT lasting 30 seconds or appropriate implantable cardioverter-defibrillator therapy including anti-tachycardia pacing or shock.
Acute hemodynamic decompensation is defined by escalation of at least 1 new high dose inotrope/pressor occurring after anesthesia induction with persistent requirement during stable rhythm, >20% drop in cardiac index, unplanned insertion of percutaneous hemodynamic support device.
Measured: 6 months
Secondary outcomes (7)
VT burden (ICD therapy including shocks and ATP, sustained VT episodes >30 seconds)
Total number of ICD therapies (ATP and shocks) and recorded sustained VT episodes>30 seconds, compared 6 months before and 6 months after ablation.
Measured: 6 months
Total Mapping Time
dwell time of multi-electrode mapping catheters
Measured: immediately at the end of the procedure
Total fluoroscopy time
Total amount of fluoroscopy time during the entire procedure
Measured: immediately at the end of the procedure
total procedural time
time from introduction of catheters to removal of catheters
Measured: immediately at the end of the procedure
Procedural adverse events or complications
Major complications include: new acute pericardial effusion requiring intervention, vascular complication requiring intervention, embolic stroke confirmed by brain imaging, limb ischemia requiring intervention, or bacteremia.
Major adverse events include: cardiogenic shock (requiring escalation of inotropes or salvage mechanical circulatory support)
Measured: 1 month
Use of general anesthesia
Whether general anesthesia (intubation) is required/used during the procedure
Measured: immediately at the end of the procedure
Acute heart failure readmission
unexpected readmission after index ablation discharge
Measured: 1 month
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Jun 2024
- Study start18 Mar 2026
- Primary completion28 Sep 2029 (estimated)
- Study completion1 Apr 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Ventricular TachycardiaStudies of the same condition, open and under way.
- More trials run by VA Office of Research and DevelopmentThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Randomized controlled trial
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 36 participants (estimated)
Sponsor and investigators
- Lead sponsor
- VA Office of Research and Development
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
- Investigators
- Gordon Ho, MD, Principal investigator, VA San Diego Healthcare System, San Diego, CA
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06464315
- Sponsor's protocol ID
- CARA-007-23F
- Acronym
- SLO-VT
- Status last verified
- Mar 2026
- First submitted
- 23 May 2024
- Last updated
- 25 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 25 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Functional Substrate-Only Mapping Technique to Guide Ablation of Arrhythmogenic Substrate Underlying Ventricular Tachycardia
- ClinicalTrials.gov ID
- NCT06464315
- Acronym / sponsor ID
- SLO-VT / CARA-007-23F
- Conditions
- Ventricular Tachycardia, Sudden Cardiac Death
- Keywords
- functional substrate mapping, conduction slowing, isochronal late activation mapping (ILAM), peak frequency signal analysis, deceleration zones
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 36 participants (estimated)
- Lead sponsor
- VA Office of Research and DevelopmentUS federal agency
- Study start
- 18 Mar 2026 (actual)
- Primary completion
- 28 Sep 2029 (estimated)
- Study completion
- 1 Apr 2030 (estimated)
- First posted
- 18 Jun 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Ventricular tachycardia (VT) is a leading cause of death and suffering in the Veteran population. Currently, ablation procedures are performed to destroy the diseased tissue that causes this problem. This study will test to see if an experimental strategy of only targeting regions of slow conduction without the induction of VT can improve the efficacy and safety of VT ablation. Once this study is completed, the investigators will know whether this ablation strategy could help increase the efficacy, safety and efficiency of ablation therapy of fatal heart rhythms.
Detailed description
Ventricular tachycardia (VT) remains a leading cause of death and morbidity in the veteran population, but current ablation procedures to treat VT are limited by hemodynamic instability of induced VT during standard invasive activation mapping (up to 80% of induced VT), lengthy ablation procedures (~8 hours), and difficulty in accurately localizing the critical origination sites of VT. The long-term goal is to simplify VT ablation using invasive functional substrate mapping techniques to improve the safety, efficacy, and efficiency of VT catheter ablation. The overall objectives in this application are to i) perform a randomized clinical trial to test whether performing simplified VT ablation guided only by invasive functional substrate mapping without VT induction improves the safety and efficiency of VT ablation while maintaining similar efficacy compared to standard ablation and ii) mechanistically correlate abnormal functional substrate with VT origination sites localized using gold standard invasive activation mapping. The central hypothesis is that ablation of slowly conducting tissue characterized by high frequency signals is sufficient to eliminate VT and improves clinical outcomes of VT ablation. The rationale is that recently developed sophisticated techniques to characterize functionally abnormal tissue can localize critical VT-sustaining substrate without needing to subjecting patients to mapping of hemodynamically unstable VT which is routinely done during standard of care ablation. The central hypothesis will be tested by pursuing one primary specific aim: Perform a randomized clinical trial to determine whether VT ablation guided only by invasive functional substrate mapping without VT induction decreases procedure time, fluoroscopy time, and procedural complications while maintaining similar efficacy compared to standard VT ablation controls. This study also includes 2 sub-aims to uncover VT mechanisms characterizing the distance of slowly conducting tissue to VT exit sites and provide a method to unmask critical arrhythmogenic substrate in non-ischemic cardiomyopathy patients in whom scar is not easily identified. The research proposed is innovative because it tests a novel strategy using new algorithms that can identify the critical tissue sustaining VT without requiring the induction of VT. The proposed research is significant because a functional substrate-guided only approach to VT ablation while still localizing the critical tissue causing VT is expected to increase the safety, efficacy, and efficiency of treating a fatal heart rhythm disorder
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized controlled trial
| Arm | Type | Receives |
|---|---|---|
| Functional substrate mapping only without VT induction | Experimental | Procedure: Functional Substrate-Only Mapping without VT InductionIn this experimental arm, only functional substrate mapping will be used to guide ablation of conduction slowing regions, without VT induction or mapping during VT. Ablation targets of conduction slowing will be identified as: 1) deceleration zones of conduction slowing, previously defined as 3 isochrones coalescing within 1cm radius. 2) wavefront discontinuities represented by lines of conduction block, previously defined as late potentials with at least 20ms of isoelectric segment, and 3) regions of slow conduction characterized by high peak frequency (220-500Hz), which uses spectral frequency analysis to identify signals with highest frequency as a surrogate for slow conduction. All regions exhibiting any of these 3 surrogates of slow conduction will be ablated. |
| Standard VT Mapping | Active comparator | Procedure: Standard-of-Care Mapping/ImagingStandard-of-care mapping, including voltage mapping of intrinsic rhythm, entrainment, activation, and/or pace mapping, will be performed to guide VT ablation. Standard VT induction protocols will be performed. |
Who may qualify
- Ages
- 18 to 90 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Men and women >18 years of age referred for clinically indicated VT ablation and experience monomorphic or polymorphic scar-based VT documented by telemetry, ICD interrogation, ECG or event monitoring.
- Scar-based VT is defined as VT in patients with structural heart disease (assessed with either abnormal nuclear perfusion imaging (>5% defect), late gadolinium uptake on cardiac MRI, wall thinning <10mm or calcified myocardium on cardiac CT, akinesis or hypokinesis on echocardiogram, presence of Q waves on ECG, history of myocardial infarct).
- Patients undergoing epicardial VT ablation and who undergo prophylactic percutaneous hemodynamic support devices will also be included.
Key exclusion criteria (7 listed)
- Patients without structural heart disease will be excluded from the pri-mary analysis, but enrolled in a prospective registry
- Patients who are pregnant
- Presence of intracardiac thrombus
- active acute coronary ischemia with unrevascularized coronary artery disease (CAD >70% stenosis)
- Active bacteremia
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Functional Substrate-Only Mapping without VT InductionAlso: Isochronal late activation mapping (ILAM), peak frequency analysisIn this arm, invasive maps will be constructed by annotating the latest deflection and peak frequency during voltage mapping of stable intrinsic rhythm to localize areas of slow conduction. Annotated algorithms are cleared by the FDA. No VT will be purposefully induced in this experimental arm. | Procedure or surgery | Functional substrate mapping only without VT induction |
| Standard-of-Care Mapping/ImagingConventional invasive scar (voltage) and electrical VT (entrainment, activation, pace) mapping will be used to guide VT ablation. Functional substrate mapping will not be used in this arm. VT will be induced using standard protocols. | Procedure or surgery | Standard VT Mapping |
Primary outcome
Time to composite endpoint (VT recurrence, death, or acute hemodynamic decompensation)
Time frame: 6 months
Ventricular arrhythmia recurrence is defined by an episode of sustained VT lasting 30 seconds or appropriate implantable cardioverter-defibrillator therapy including anti-tachycardia pacing or shock. Acute hemodynamic decompensation is defined by escalation of at least 1 new high dose inotrope/pressor occurring after anesthesia induction with persistent requirement during stable rhythm, >20% drop in cardiac index, unplanned insertion of percutaneous hemodynamic support device.
7 secondary outcomes
VT burden (ICD therapy including shocks and ATP, sustained VT episodes >30 seconds)
Time frame: 6 months
Total Mapping Time
Time frame: immediately at the end of the procedure
Total fluoroscopy time
Time frame: immediately at the end of the procedure
total procedural time
Time frame: immediately at the end of the procedure
Procedural adverse events or complications
Time frame: 1 month
Use of general anesthesia
Time frame: immediately at the end of the procedure
Acute heart failure readmission
Time frame: 1 month
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Mar 2026.
- Individual participant dataSharing planned: No
Related trials for Ventricular Tachycardia
Not yet recruiting
MRI-guided Ventricular Tachycardia Ablation in Patients With Structural Heart Disease
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VINTAGE (Ventricular Intramyocardial Navigation for Tachycardia Ablation Guided by Electrograms) Using Commercial Off-The-Shelf (COTS) Catheters
Ventricular Arrhythmia
Recruiting
Safety and Effectiveness of the Sphere-9™ Catheter and Affera™ Ablation System for the Treatment of Ventricular Tachycardia (Sphere VT)
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A Study of SGT-501 Gene Therapy in Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)
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SPIKE FLOW Endocardial Lead Safety and Performance Study
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Gordon Ho, MD principal investigator
VA San Diego Healthcare System, San Diego, CA
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Functional Substrate-Only Mapping without VT Induction and Standard-of-Care Mapping/Imaging in people with Ventricular Tachycardia and Sudden Cardiac Death, run by VA Office of Research and Development at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 25 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time to composite endpoint (VT recurrence, death, or acute hemodynamic decompensation) (time frame: 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Mar 2026.