Comparison of VF Induction Techniques During Medtronic ICD Implant (VF) (ICD) (VF)

April 23, 2018 updated by: James Merrill

Comparison of Ventricular Fibrillation Induction Techniques During Medtronic Implantable Cardioverter Defibrillator Implant

As the indications for Implantable Cardioverter Defibrillator implantation expand, minimizing implant time is critical. Also, patients receiving biventricular ICDs are sometimes more unstable and minimization of sedation time is crucial. Multiple induction attempts, with a 1-Joule shock, can cause disruption in lead position. Therefore limiting the number of attempts will allow for better lead stability throughout the procedure and a more straightforward implant process.

Investigator proposes a detailed documentation of success rates from various Ventriculart Fibrillation induction methods during implant of Medtronic defibrillation capable devices.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Our clinical experience has found that attempts to induce patients receiving ICDs at implant using the nominal Medtronic T-shock settings are not always effective at inducing ventricular fibrillation. When this results, a change to the parameters for T-shock is made before reattempting to induce ventricular fibrillation in patients undergoing ICD implantation.

Another available induction method is 50 Hz Burst. "The 50 Hz Burst induction is designed to induce VF by delivering a rapid burst of pacing pulses. The amplitude and pulse width of these pulses are selectable, but the pacing interval is fixed at 20 ms."2 If multiple attempts using the T-shock method are unsuccessful, 50 Hz Burst provides an additional method for inducing ventricular fibrillation. It is a less desirable method since it can result in very fine VF that is difficult to identify the initiation of possibly resulting in longer times in VF causing higher defibrillation threshold or in undersensing due to the fine nature of the rhythm.

T-shock has been found to be a fast and reliable method for inducing ventricular fibrillation in ICD implants. Greater success of inducing ventricular fibrillation using the T-shock method has been found when the energy of the T-shock was higher and the coupling interval was shorter. In addition, increasing the shock strength increases the window of vulnerability. For the T-shock method to be most efficient, initial success at inducing ventricular fibrillation, and therefore a reduced number of attempts, is important. This requires a better understanding of the optimal programmed settings for the initial T-shock induction attempt.

Moreover, in recent years, ICD indications have grown to include primary prevention patients. These patients may have different vulnerable periods than patients previously evaluated to develop Medtronic nominal settings.

Our clinical experience has found that the nominal T-shock settings are only effective at inducing ventricular fibrillation approximately seventy-five percent of the time. However, a detailed collection of success rates has not been performed.

Study Type

Interventional

Enrollment (Actual)

100

Phase

  • Not Applicable

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

    • Tennessee
      • Kingsport, Tennessee, United States, 37660
        • Wellmont CVA Heart Institute

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 and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • All patients undergoing Medtronic ICD or Cardiac Resynchronization Therapy-Defibrillator implant (initial implant or generator replacement) will be included.

Exclusion Criteria:

  • Any patient who is medically unstable and testing is deemed unsafe by physician will be excluded from this study.

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Nominal Parameter
Nominal T shock setting
Nominal Parameter Set 1 Programming Values for EnTrust
Other Names:
  • Medtronic ICDs
Experimental: Experimental Parameter
Educated T shock setting
Experimental Parameter Set 2 Programming Values
Other Names:
  • Medtronic ICDs

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sustained Ventricular Fibrillation
Time Frame: 2 hours
The primary endpoint is the successful induction of sustained ventricular fibrillation.
2 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Factors
Time Frame: 2 hours
Determine if any pre-implant patient demographics are factors impacting T-shock success according to parameter settings.
2 hours

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Safety Monitoring
Time Frame: 2 hours
Number of participants that were monitored for safety issues, including increased heart rate, blood pressure, decreased oximetry levels, and stable rhythm during the entire procedure.
2 hours

Collaborators and Investigators

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

Sponsor

Collaborators

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

January 1, 2011

Primary Completion (Actual)

August 1, 2012

Study Completion (Actual)

August 1, 2012

Study Registration Dates

First Submitted

December 31, 2013

First Submitted That Met QC Criteria

January 2, 2014

First Posted (Estimate)

January 6, 2014

Study Record Updates

Last Update Posted (Actual)

May 22, 2018

Last Update Submitted That Met QC Criteria

April 23, 2018

Last Verified

April 1, 2018

More Information

Terms related to this study

Other Study ID Numbers

  • VF Induction

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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