Testing Objective Methods for Template Matching Ventricular Tachycardia and Pacemapping

May 13, 2016 updated by: John Sapp

Quantitative Measurements Comparing Body Surface Potentials During Pacemapping and Spontaneous Ventricular Tachycardia

Patients sometimes suffer from life-threatening abnormal heart racing that originates from the lower chamber of the heart. These patients will often need an implantable defibrillator which has the ability to shock the heart back to a normal heart rhythm, but this does not prevent them from getting frequent recurrences of the bad heart rhythm needing shocks from the device. This can be painful and potentially harmful. Medicines to prevent recurrences of shocks are not very effective and have many side effects. An alternative to medicines for this is a procedure called a catheter ablation in which a wire is passed up through the blood vessels of the leg into the heart and used to find the short circuits which cause the dangerous heart rhythm. When the spot causing the trouble is found, the investigators can burn it ("ablate" it). This procedure is challenging and methods are needed to make it more effective and easier to do. One of the main ways for finding the short circuits involves using the electrocardiogram (the "ECG"). The regular ECG is simplistic and only makes use of recordings from 10 sites (6 precordial sites and 4 sites on both upper and lower limbs) on the body surface. The investigators are testing whether making recordings from 120 sites on the chest and back and using special computerized analysis of the recordings can help make catheter ablation for dangerous heart rhythms more effective.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Several conventional and advanced mapping techniques are frequently utilized to accomplish a successful catheter ablation. Many of these mapping techniques (activation mapping, entrainment mapping) are hampered by either hemodynamic instability of some tachycardias or non-sustainability of others. Pacemapping is a commonly used tool for mapping non-sustained or hemodynamically unstable VT, which is based upon the principle that activation of the heart from a given site will yield a reproducible body surface electrocardiogram (ECG) morphology and that pacing from a site very close to the site at which VT activates the heart will result in a matching ECG morphology. This technique, however, is limited by imperfect accuracy and spatial resolution, subjectivity of interpretation leading to marked inter-observer variability in the perceived quality of a morphologic match, and by the need for an intuitive interpretation of the ECG to direct catheter manipulation. We hypothesize that one can improve the accuracy with which the origin of VT is localized by applying body surface potential mapping (BSPM), using data derived from 120 simultaneously acquired ECGs.

Objectives:

  1. To quantify the similarity between BSPM waveforms during induced VT and during pacemapping or between two different pacing sites using two waveform comparison metrics, the correlation coefficient (CORR) and the root mean square error (RMSE) and to test the validity of these metrics as markers of proximity of the pacing site to the site of earliest ventricular activation.
  2. To compare the accuracy with which the origin of ventricular tachycardia is localized via pacemapping by applying (BSPM), which uses data derived from 120 simultaneously acquired ECGs, to the accuracy of localization with different ECG subsets e.g. 12-lead ECG and X, Y and Z leads.

Patient and methods:

We anticipate that our patients will fall in one of the flowing 4 groups:

Group A:Patients with focal VT in structurally normal heart. Group B:Patients with scar related VT in which the exit site can be identified. Group C:Patients with scar related VT in which the exit site cannot be identified.Group D:Patients presenting with SVT.

For all groups, data for body-surface potential mapping (BSPM) will be recorded during induced VT (Group A& B), pacing from virtual VT exit sites which are several points selected around the scar margin to represent the VT exit site (group C) or index pacing site which is a pacing site selected as a reference in the RV of patients presented with SVT (group D) and from different pacemapping sites including successful and unsuccessful ablation sites if applicable. All data will be imported into customized software.

The improvement in the arithmetic value of the two comparison metrics will be tested as the site of pacing approaches the site of earliest ventricular activation (Groups A&B) or virtual VT exit sites in group C or the index pacing site (in group D). The best CORR and RMSE between the BSPM obtained during VT (in group A and B)/virtual VT exit sites (in group C) or index pacing site (group D) and different pacing sites (including successful and unsuccessful ablation sites) will be recorded. A simple linear regression will be used to compare the CORR and RMSE difference at each pacing site to distance between this pacing site and the successful ablation site as a surrogate of the best pace-match (in group A and B) or the corresponding virtual VT exit site (in group C) or index pacing site (group D). P value <0.05 will be considered significant. The mean sensitivity, specificity, and positive- and negative-predictive accuracies of the arithmetic metrics in determining the VT origin/exit site will be determined. We will repeat the previous protocol using different ECG subsets including 12 lead ECGs and X, Y and Z leads. The predictive accuracies for different subsets of electrodes will be measured and compared to those derived from using the whole BSPM obtained from the 120 ECG leads.

Study Type

Observational

Enrollment (Actual)

20

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Nova Scotia
      • Halifax, Nova Scotia, Canada, B3H 3A7
        • Capital District Health Authority

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients will be recruited from consecutive patients referred for ablation of sustained ventricular tachycardia with or without structural heart disease or Patients referred for ablation of supraventricular tachycardia to the QEII Health Sciences Centre, in Halifax, NS.

Description

Inclusion Criteria:

  • All patients presenting with sustained monomorphic VT who are amenable to VT ablation.
  • Patients referred for ablation of supraventricular tachycardia.

Exclusion Criteria:

  • Patients presenting with ventricular tachycardia if no sustained tachycardia can be induced, or if in that particular patient pace-mapping is known to be an inaccurate method of mapping (e.g. in bundle branch reentry VT or fascicular VT).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
12-Lead Body Surface Mapping - Focal VT .
Body surface mapping (BSM) will be completed in patients with a defined focal VT site during the EP study.
Other: 12-lead body surface mapping
An average of 20 distinct left ventricular sites will be mapped using 12-lead body surface mapping electrodes and recorded for 15 seconds, then sent to a computer for further analysis.
12-Lead BSPM - Scar related VT, exit not identified
Body surface mapping will be competed on patients with scar related VT where the exit cannot be identified
Other: 12-lead body surface mapping
An average of 20 distinct left ventricular sites will be mapped using 12-lead body surface mapping electrodes and recorded for 15 seconds, then sent to a computer for further analysis.
12-Lead BSPM - Scar related VT exit identified
Body surface mapping will be competed on patients with scar related VT where the exit is identified
Other: 12-lead body surface mapping
An average of 20 distinct left ventricular sites will be mapped using 12-lead body surface mapping electrodes and recorded for 15 seconds, then sent to a computer for further analysis.
12-Lead BSPM - Supraventricular tachycardia
Body surface mapping will be completed on patients requiring an EP study for the treatment of symptoms related to supraventricular tachycardia
Other: 12-lead body surface mapping
An average of 20 distinct left ventricular sites will be mapped using 12-lead body surface mapping electrodes and recorded for 15 seconds, then sent to a computer for further analysis.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Correlating the arithmetic markers (CORR and MAD) to the distance between the pacing site and origin of the ventricular tachycardia or the index pacing site.
Time Frame: One year
One year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

John Sapp

Investigators

  • Principal Investigator: John A Sapp, MD, FRCPC, Nova Scotia Health Authority

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2010

Primary Completion (Actual)

July 1, 2011

Study Completion (Actual)

July 1, 2011

Study Registration Dates

First Submitted

July 25, 2010

First Submitted That Met QC Criteria

July 26, 2010

First Posted (Estimate)

July 27, 2010

Study Record Updates

Last Update Posted (Estimate)

May 17, 2016

Last Update Submitted That Met QC Criteria

May 13, 2016

Last Verified

May 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SP12

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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