Precise Measurement of Pediatric Defibrillation Thresholds

July 24, 2017 updated by: Andrew Eric Radbill, Boston Children's Hospital

Defibrillation Thresholds in a Pediatric Cohort Using Binary Search Protocol

Patients who receive an implantable cardioverter-defibrillator (ICD) usually undergo testing at the end of the ICD procedure to measure the amount of energy able to successfully defibrillate the heart (defibrillation threshold testing, or DFT). This study proposes to perform that measurement in pediatric patients already undergoing clinically necessary ICD procedures, with the measurement performed using a binary search method that has been previously validated in adult cohorts. We hypothesize that pediatric DFTs, when precisely measured, may be lower than previously assumed from extrapolation of adult data.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
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

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
        • Children's Hospital Boston

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

All patients seen by the electrophysiology service at Children's Hospital Boston who are identified to be at very high risk of sudden cardiac death and in need of an ICD

Description

Inclusion Criteria:

  • Current follow-up at Children's Hospital Boston
  • Children with current or planned ICDs who are scheduled by their primary electrophysiologist for clinically necessary assessment/re-assessment of defibrillation threshold
  • If the patient has an ICD system with a non-transvenous shock coil: weight ≤35kg at time of initial implant, with current weight <50kg
  • If the patient has an ICD system with a conventional transvenous shock coil: current weight ≤60kg

Exclusion Criteria:

  • Clinical failure of any system component not able to be addressed by hardware repair or exchange
  • Hemodynamic instability that in the judgment of the primary electrophysiologist warrants abbreviation of DFT assessment
  • Unsuccessful induction of fibrillation during DFT testing

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

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Pediatric ICD pts
Inclusion criteria for study participants included: 1) weight ≤60 kg, 2) new or existing ICD system, and 3) clinically necessary assessment of the defibrillation efficacy of the ICD system. Transvenous systems utilized a high-voltage ICD coil with active-fixation lead attached to the right ventricular endocardial surface, whereas non-transvenous systems depended upon a high-voltage shocking coil placed within the pericardial, subcutaneous or pleural space. To be included in the post-shock pacing portion of the study, adequate sinus and AV node function had to be present at baseline. Exclusion criteria included 1) tenuous hemodynamic status felt to warrant abbreviation of the defibrillation efficacy testing or 2) inability to induce fibrillation during defibrillation threshold testing (DFT).
Diagnostic test: Defibrillator threshold testing
Measurement of the defibrillation threshold was performed using a modified binary search protocol. This protocol specified three distinct inductions of ventricular fibrillation (VF) for all subjects, with a 3-5 minute observation/waiting period between inductions. The initial shock energy was programmed at 9 joules (J) for all patients, with internal rescue shocks at 31J followed by device-specific maximum deliverable energy. The outcome of the initial induction determined the programmed energies for both the initial and internal rescue shocks for the second induction, and likewise for the third induction. All shocks were biphasic and delivered at manufacturers' default tilt, polarity and duration, and all final programmed shock vectors included an active can. External defibrillation pads were in place for delivery of external rescue shock should the internal shocks fail.
Other: Observation of post-shock intrinsic cardiac rhythm
Prior to each of the three ventricular fibrillation inductions performed as part of the binary search protocol, post-shock pacing was re-programmed using a pre-determined, stepwise protocol that progressively decreased the lower rate limit. For the purpose of this protocol, post-shock pacing was considered necessary if 1) ≥7 ventricular-paced beats or 2) asystole >4 seconds was observed in the first 20 seconds after defibrillation, or if the systolic blood pressure demonstrated a >10% decrease from pre-induction baseline at follow-up measurement 1 minute post-defibrillation. Rescue ventricular pacing via the programmer was available for all subjects.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Defibrillation Threshold
Time Frame: During clinical ICD procedure, as a single event
The defibrillation threshold is a measure of the minimum amount of energy (in Joules) that is able to successfully defibrillate an episode of ventricular fibrillation. This measurement is specific to each individual patient with his/her specific defibrillator configuration. There are several different strategies to measuring this in an individual patient; this study utilized the binary search protocol.
During clinical ICD procedure, as a single event

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Do DFTs Vary by Type of ICD Systems Implanted?
Time Frame: During clinical ICD procedure, as a single event
The defibrillation threshold (as measured in Joules as already described in the details regarding the primary outcome) will be compared between patients with two distinct general types of implanted defibrillator systems: 1) transvenous ICD systems (defibrillator leads located inside the vein and attached to the endocardial surface of the heart) and 2) non-transvenous ICD systems (including all other types of debrillation systems).
During clinical ICD procedure, as a single event
Intrinsic Heart Rate in the Immediate Post-defibrillation Period
Time Frame: During clinical ICD procedure, as a single event
A patient will be considered to have an intrinsic slow heart rate in the period of time immediately following defibrillation (20 seconds) if any of the following are observed: >7 paced beats, asystole >4 seconds, or experienced >10% decrease in systolic blood pressure.
During clinical ICD procedure, as a single event

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Boston Children's Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Andrew E Radbill, MD, Boston Children's Hospital

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 4, 2009

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 26, 2010

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 10, 2012

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 6, 2010

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 6, 2010

First Posted (Estimate)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 7, 2010

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 5, 2018

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 24, 2017

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2017

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 09-04-0209

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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