Precise Measurement of Pediatric Defibrillation Thresholds
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|ClinicalTrials.gov Identifier: NCT01043562|
Recruitment Status : Completed
First Posted : January 7, 2010
Results First Posted : February 5, 2018
Last Update Posted : February 5, 2018
|Condition or disease||Intervention/treatment|
|Pediatrics Defibrillators, Implantable||Diagnostic Test: Defibrillator threshold testing Other: Observation of post-shock intrinsic cardiac rhythm|
|Study Type :||Observational|
|Actual Enrollment :||20 participants|
|Official Title:||Defibrillation Thresholds in a Pediatric Cohort Using Binary Search Protocol|
|Actual Study Start Date :||June 4, 2009|
|Actual Primary Completion Date :||May 26, 2010|
|Actual Study Completion Date :||May 10, 2012|
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.
- 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.
- 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).
- 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.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01043562
|United States, Massachusetts|
|Children's Hospital Boston|
|Boston, Massachusetts, United States, 02115|
|Principal Investigator:||Andrew E Radbill, MD||Boston Children’s Hospital|