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POWER (Pulse Width Optimized Waveform Evaluation Trial)

This study has been completed.
Information provided by (Responsible Party):
St. Jude Medical Identifier:
First received: April 3, 2006
Last updated: July 27, 2012
Last verified: July 2012

April 3, 2006
July 27, 2012
August 2006
April 2008   (final data collection date for primary outcome measure)
  • Defibrillation Thresholds (DFTs) (3.5 ms Waveform) [ Time Frame: Implant ] [ Designated as safety issue: No ]
  • DFT (2.5 ms Waveform) [ Time Frame: Implant ] [ Designated as safety issue: No ]
  • DFT (4.5 ms Waveform) [ Time Frame: Implant ] [ Designated as safety issue: No ]
Difference between the defibrillation threshold estimates (voltage & energy) for 2.5, 3.5 and 4.5 ms membrane time constant based biphasic defibrillation waveforms
Complete list of historical versions of study NCT00311181 on Archive Site
Not Provided
  • NYHA Class
  • High Voltage Impedance
  • QT Interval
  • Cardiac Dimension
  • Antiarrhythmic Drug Therapy
Not Provided
Not Provided
POWER (Pulse Width Optimized Waveform Evaluation Trial)
Phase 4 Study That Compares the DFT (Defibrillation Threshold) Efficacy of 3 Different Membrane Time Constant Based Biphasic Defibrillation Waveforms

The objective of this study is to compare the ULV (Upper Limit of Vulnerability)/DFT (Defibrillation Threshold) efficacy between the 2.5, 3.5 and 4.5 ms membrane time constant based biphasic defibrillation waveforms. This comparison will result in identifying the optimal membrane time constant when programming the "tuned" defibrillation waveform.

Sudden cardiac death (SCD) continues to be a significant cause of cardiac mortality with annual deaths ranging from 250,000 to 400,000 in the United States. Accordingly, implantable cardioverter-defibrillators (ICD's) have proven to be an important therapeutic option for patients susceptible to SCD. Successful therapy and generator longevity are greatly dependent on proper defibrillation threshold (DFT) determination.

All modern ICD's utilize a biphasic waveform for defibrillation. It has been clearly shown that biphasic waveforms reduce the energy required for internal defibrillation of the heart. However, there is no consensus on which pulse widths are best for defibrillation.

St. Jude Medical ICD's (implantable cardioverter defibrillators) have programmable pulse widths, which allow the physician multiple options in dealing with ICD patients. By implanting ICD's with programmable pulse widths, this study utilizes the Tissue RC Resistance/Capacitance) model to try to identify the optimal pulse widths.

To determine the efficacy of an optimal membrane time constant estimate for the "tuned" waveform, defibrillation testing must be performed. Upper limit of vulnerability (ULV) has been proposed as an alternative means of predicting the DFT and it has been shown that ULV guided DFT testing can achieve a defibrillation success rate of 95%.

Phase 4
Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Single Group Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
Sudden Cardiac Death
Device: Implantable Cardioverter Defibrillator (ICD), Cardiac Resynchronization Therapy (CRT-D)
Patients that are indicated for an ICD or CRT-D receive one of these devices.
Experimental: 2.5/3.5/4.5 ms defibrillation waveform
Intervention: Device: Implantable Cardioverter Defibrillator (ICD), Cardiac Resynchronization Therapy (CRT-D)
Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
April 2008
April 2008   (final data collection date for primary outcome measure)

Inclusion Criteria:

  • Patient is a candidate for ICD/CRT-D implantation.
  • Patient has a compatible transvenous defibrillation lead system.
  • Patient has had an echocardiogram, MUGA, or cath procedure within 6 months of ICD/CRT-D implant.
  • Patient is able to tolerate ULV guided DFT testing.

Exclusion Criteria:

  • Patient has a mechanical valve in the tricuspid position.
  • Patient has epicardial defibrillation electrodes.
  • Patient is pregnant.
  • Patient is less than 18 years old.
18 Years and older
Contact information is only displayed when the study is recruiting subjects
United States
CRD 324
St. Jude Medical
St. Jude Medical
Not Provided
Principal Investigator: Shephal Doshi, MD Pacific Heart Institute
St. Jude Medical
July 2012

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP