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Trial registered on ANZCTR


Registration number
ACTRN12620000049976
Ethics application status
Approved
Date submitted
2/12/2019
Date registered
22/01/2020
Date last updated
5/08/2021
Date data sharing statement initially provided
22/01/2020
Type of registration
Prospectively registered

Titles & IDs
Public title
Targeted ablation for ventricular tachycardia (VT)
Scientific title
Does tissue microarchitecture-information based ventricular tachycardia (VT) ablation in patients with an implantable cardioverter defibrillator affect the frequency of subsequent VT?
Secondary ID [1] 297981 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
ventricular tachycardia 312393 0
Condition category
Condition code
Cardiovascular 310951 310951 0 0
Other cardiovascular diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Exposure: Patients will be eligible if they had had a myocardial infarction, had undergone placement of an implantable cardioverter defibrillator (ICD), and had >1 episode of sustained VT or ICD therapy during treatment with anti-arrhythmic drugs within the previous 6 months.

Intervention: The intervention will be limited VT ablation, in comparison to conventional VT ablation. Limited ablation involves mapping cardiac conduction in sinus rhythm and performing minimal ablation to 1-5 ventricular regions that are designated as critical for VT maintenance by a computer algorithm. The computer-based algorithm is an experimental software developed for the purpose of study. It is based on previous pre-clinical and clinical work and determines a tissue's propensity to be part of VT circuits based on its electrical information in time- and voltage-domain in sinus rhythm. The overall electrogram information is displayed in 3 color-coded maps: mean activation, dispersion in activation and Shannon entropy, and a VT supporting region is identified where sites with latest mean activation, high dispersion and least entropy are clustered together in a small region. Post-ablation, ablation success will be tested by checking VT inducibility using programmed pacing of right or left ventricle with multiple rapid premature stimuli. If VT remains inducible after limited ablation, conventional ablation will be performed.
Ablation will be performed by experienced cardiac electrophysiologists at The Townsville hospital. Ablation involves focal application of radiofrequency energy (up to 50Watts as per operator preference) using commercial irrigated steerable catheters enabled with specialized sensors that detect location, force and tip temperature. Typically, limited VT ablation procedure is expected to be of 3-5hours duration, and is comparable to a standard approach VT ablation. Procedure related complications will be recorded from the operation notes and nursing records if necessary.
Intervention code [1] 314199 0
Treatment: Surgery
Comparator / control treatment
The control group will be made up of patients receiving conventional ablation treated through the standard approach whereby all abnormal tissues in the ventricle will be targeted with catheter ablation. The precise selection of target sites for ablation will be left to the investigator with the following guidelines: Ablation sites will be required to have abnormal low-amplitude electrograms, wide fractionated, double or late potentials, paced QRS morphology similar to target VT morphology, stimulus to QRS interval >40ms, anatomic continuity with other lesions. In cases with mappable VT, mid-diastolic potential during VT or sites with successful entrainment of VT will be targeted. Post-ablation, VT inducibility will be tested using standard pacing protocols. If VT remains inducible after limited ablation, additional ablation will be performed at the discretion of the operator.
All ablations will be performed by experienced cardiac electrophysiologisgts at the Royal Adelaide Hospital and Toronto General Hospital.
Control group
Active

Outcomes
Primary outcome [1] 319763 0
Patient will be seen in clinic every 3 months and data from their ICDs will be downloaded to detect VT events at follow-up. The primary outcome of the study will be recurrent VT storm or intermittent VT within 6-months of the procedure.
Timepoint [1] 319763 0
Within 6 months of procedure
Secondary outcome [1] 369442 0
Acute success determined by non-inducibility of clinical VT tested by programmed ventricular stimulation with 3 extrastimuli until refractoriness from RV catheter at the end of ablation.
Timepoint [1] 369442 0
Within 6 months of procedure
Secondary outcome [2] 369443 0
Hospitalization for heart failure. An hospital admission will be adjudicated as heart failure based on findings in hospital records of worsening pulmonary or peripheral congestion, and requires augmentation of diuretic therapy or intravenous vasoactive agent.
Timepoint [2] 369443 0
Within 6 months of procedure
Secondary outcome [3] 369444 0
Hospitalization for VT. An hospital admission will be adjudicated as due to VT when as per hospital records patient is admitted with a primary diagnosis of VT.
Timepoint [3] 369444 0
Within 6 months of procedure
Secondary outcome [4] 369445 0
Cardiovascular death. Death and its cause will be adjudicated using a combination of telephone follow-up, medical records and national death registry search.
Timepoint [4] 369445 0
Within 1 year of procedure

Eligibility
Key inclusion criteria

Patients will be over 18 years of age (not inclusive) and meet standard requirements for catheter ablation of VT. Patients will be eligible if they had had a myocardial infarction, had undergone placement of an implantable cardioverter defibrillator (ICD), and had >1 episode of sustained VT or ICD therapy during treatment with anti-arrhythmic drugs within the previous 6 months.
Minimum age
19 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Patients with ventricular fibrillation, previous VT ablation, acute ischemia, non-ischemic cardiomyopathy, uncontrolled heart failure, left ventricular thrombus, mechanical prosthetic valves, severe peripheral vascular disease, disease process likely to limit survival to <1year, dementia or pregnancy will be excluded.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
We assumed that the primary outcome of VT recurrence would occur in 50% of the patients in the conventional ablation group after 6-month of follow-up (Stevenson et al, Thermocool VT Trial, Circulation 2008). Accordingly, we calculated that enrolling 55 patients in each group would provide a power of 80% to determine that the absolute risk of the primary outcome would be at most 25% higher in the limited ablation group than in the conventional ablation group (non-inferiority margin, 50%) at a significance level of 0.05 (two-sided). A 10% crossover rate from limited to conventional ablation will be permissible.


All analyses will be conducted according to the intention-to-treat principle. Survival-analysis techniques will be used to compare the incidence of primary and secondary outcomes between the groups. The survival rates in each group will be summarized with the use of Kaplan-Meier estimates and compared with the use of nonparametric log rank tests. Hazard ratios and confidence intervals will be calculated with the use of Cox proportional-hazards models, which will also be used to test for interactions in the planned subgroups. The following variables will be included as candidates for subgrouping: age, prevalent heart failure, left ventricular ejection fraction, prior coronary bypass surgery, anterior myocardial infarction, time since first infarction, total number of clinical VT, maximal cycle length of VT, history of VT storm, and amiodarone therapy at the time of ablation. Descriptive variables will be summarized by means and standard deviations, means of frequency distributions, or medians and interquartile range and tested with the use of t-test, Fisher's exact test, or the Wilcoxon-Mann-Whitney test, as appropriate.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/10/2021
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
110
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
QLD,SA
Recruitment hospital [1] 13621 0
The Townsville Hospital - Douglas
Recruitment hospital [2] 13622 0
The Royal Adelaide Hospital - Adelaide
Recruitment postcode(s) [1] 26288 0
4814 - Douglas
Recruitment postcode(s) [2] 26289 0
5000 - Adelaide
Recruitment outside Australia
Country [1] 21405 0
Canada
State/province [1] 21405 0
Ontario

Funding & Sponsors
Funding source category [1] 302504 0
Hospital
Name [1] 302504 0
Townsville Hospital and Health Service
Country [1] 302504 0
Australia
Primary sponsor type
Hospital
Name
Townsville Hospital and Health Service
Address
100 Angus Smith Drive, Douglas QLD 4814
Country
Australia
Secondary sponsor category [1] 304691 0
None
Name [1] 304691 0
Address [1] 304691 0
Country [1] 304691 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 303160 0
Townsville Hospital and Health Service Human Research Ethics Committee
Ethics committee address [1] 303160 0
Ethics committee country [1] 303160 0
Australia
Date submitted for ethics approval [1] 303160 0
Approval date [1] 303160 0
07/05/2019
Ethics approval number [1] 303160 0
HREC/2019/QTHS/51347

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 92690 0
Dr Sachin Nayyar
Address 92690 0
Townsville Hospital and Health Service, 100 Angus Smith Drive Douglas QLD 4814
Country 92690 0
Australia
Phone 92690 0
+61 7 44335347
Fax 92690 0
Email 92690 0
[email protected]
Contact person for public queries
Name 92691 0
Sachin Nayyar
Address 92691 0
Townsville Hospital and Health Service, 100 Angus Smith Drive Douglas QLD 4814
Country 92691 0
Australia
Phone 92691 0
+61 7 44335347
Fax 92691 0
Email 92691 0
[email protected]
Contact person for scientific queries
Name 92692 0
Sachin Nayyar
Address 92692 0
Townsville Hospital and Health Service, 100 Angus Smith Drive Douglas QLD 4814
Country 92692 0
Australia
Phone 92692 0
+61 7 44335347
Fax 92692 0
Email 92692 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
5977Study protocol    377408-(Uploaded-02-12-2019-09-14-12)-Study-related document.doc
5978Ethical approval    377408-(Uploaded-02-12-2019-09-14-56)-Study-related document.pdf
5979Informed consent form    377408-(Uploaded-02-12-2019-09-15-40)-Study-related document.doc



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.