Electrical Safety of Implantable Cardioverter Defibrillators

January 10, 2018 updated by: University Hospital Southampton NHS Foundation Trust

Electrical Safety of Rescuers in Contact With Patients During Implanted Cardioverter Defibrillator Discharge

Patients at risk of developing life-threatening heart rhythms may require the implantation of a small device called a cardioverter-defibrillator (ICD), which constantly monitors the heart rhythm and delivers an electrical shock to the heart when indicated, in order to return the heart back to a normal rhythm. Many thousands of these devices have been implanted and are electrically active in patients who collapse and need resuscitation.

When a patient with an ICD collapses, the device may discharge without warning while a rescuer is performing external chest compressions (cardiac massage). Conventional ICDs placed below the left collar bone typically deliver 35-50 J energy when they discharge, but newer ICDs placed under the skin (S-ICD) alongside the breastbone deliver a larger energy when discharging; typically 50-80J energy.

Rescuers performing external chest compressions on a patient during conventional ICD discharge have reported the sensation of a painful electrical shock and permanent nerve damage. In these situations, rescuers appear to have been exposed to electrical current from the ICD considerably in excess of that which is considered a safe threshold.

Studies of surface current resulting from discharge of conventional ICDs have been reported in excess of 100 mA which is far in excess of the safe 1 mA limit, and puts the rescuer at considerable risk of tissue damage and possible dangerous heart rhythms. The newer S-ICDs deliver approximately 50% more energy and have the potential to result in exposure of a rescuer to even higher currents.

With increasing numbers of the S-ICDs being implanted, and the inevitability that rescuers will soon find themselves exposed to leakage current from these devices, there is a need to examine the leakage currents arising from these devices and assess any subsequent risk to a rescuer performing external chest compressions.

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.

Detailed Description

Rationale for Study:

When patients undergo elective implantation of an ICD, the device is tested by inducing ventricular fibrillation (VF) in the patient and allowing the ICD to sense, charge and discharge in an attempt to shock the patient back into a normal rhythm. This provides a controlled, elective situation in which to measure the cutaneous current on the patient's skin which is the current to which a rescuer could potentially be exposed.

By understanding the leakage currents from these devices, the investigators will be able to better understand the safety of rescuers in contact with patients fitted with an ICD and make specific recommendations to enable to safe undertaking of uninterrupted external chest compressions while the ICD may be discharging.

STUDY OBJECTIVES

Primary Objective:

To measure cutaneous leakage current on the chest wall during conventional and S-ICD discharge.

Secondary Objectives:

To make recommendations based on this data regarding the safety of rescuers in contact with a patient during ICD discharge.

ENDPOINTS

Primary Endpoint:

Maximum cutaneous current measured at multiple sites on the chest wall during ICD discharge.

STUDY DESIGN This is a prospective cohort study, aiming to study sequential patients undergoing elective ICD implantation and testing over a 12 month period at University Hospital Southampton.

The patient will undergo elective ICD implantation according to normal protocol. There will be no change in their treatment. After induction of general anaesthesia, an array of small self-adhesive electrodes (similar to ECG 'dots') will be placed on the patient's chest wall, and connected to a multichannel recording device.

After implantation of the ICD, the device will be tested as per normal protocol. VF is induced in the patient. The ICD senses this arrhythmia, charges and immediately delivers a shock to the myocardium. As this shock is delivered, the investigators will record the current reaching the surface electrode array using the multichannel recorder. Most patients only require one shock as defibrillation rates with ICDs are >90%. If a second shock is required, the ICD will charge automatically and discharge once again. If this occurs, the investigators will also measure the cutaneous current at this second, higher energy level. The study is then concluded. Any subsequent shocks are delivered through external paddles and the investigators would not require any data from this stage of the procedure.

STUDY POPULATION Number of Participants The investigators aim to assess 20 patients undergoing conventional ICD implantation and a further 20 patients undergoing S-ICD implantation.

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.
25

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 Kingdom
    • Hampshire
      • Southampton, Hampshire, United Kingdom, SO16 6YD
        • University Hospital Southampton

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

  • ADULT
  • OLDER_ADULT
  • CHILD

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients with implanted defibrillators (ICDs) undergoing defibrillation testing.

Description

Inclusion Criteria:

  • Patients with implanted defibrillators (ICDs) undergoing defibrillation testing
  • Patients undergoing ICD implantation that requires a defibrillation test at the end of the implantation.

Exclusion Criteria:

  • Enrolment in other ICD-related studies
  • Patients <18 yrs age

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.
Transvenous ICD
Patients with a transvenous ICD undergoing defibrillation testing.
Other: Surface current measurement
Measurement of surface current between electrodes placed on the chest wall during defibrillation
Subcutaneous ICD
Patients with a subcutaneous ICD undergoing defibrillation testing.
Other: Surface current measurement
Measurement of surface current between electrodes placed on the chest wall during defibrillation

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
Surface current during defibrillation
Time Frame: Approximately 10 mSec as the ICD discharges (i.e. at the time of testing)
To measure cutaneous leakage current on the chest wall during conventional and S-ICD discharge.
Approximately 10 mSec as the ICD discharges (i.e. at the time of testing)

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.
University Hospital Southampton NHS Foundation Trust

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 (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.
February 1, 2014

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.
January 1, 2018

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.
January 1, 2018

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).
August 29, 2017

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.
September 1, 2017

First Posted (ACTUAL)

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.
September 5, 2017

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.
January 11, 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.
January 10, 2018

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.
January 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • 13/SC/0427

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Please contact researchers directly

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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