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T-wave Alternans and Intrathoracic Impedance Measurements

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ClinicalTrials.gov Identifier: NCT00669682
Recruitment Status : Completed
First Posted : April 30, 2008
Results First Posted : March 28, 2013
Last Update Posted : April 19, 2013
Information provided by (Responsible Party):

April 28, 2008
April 30, 2008
February 15, 2013
March 28, 2013
April 19, 2013
August 2008
April 2012   (Final data collection date for primary outcome measure)
Number of Positive Twave Studies and Concurrent Positive Optivol Measurement [ Time Frame: upto 3 years ]
We wanted to examine whether positive Optivol status corresponded to a higher likelihood of a positive T wave study. The T wave alternans result is determined by a proprietary device that measures T wave and reports the result as negative, positive, or indeterminate. The Optivol measurement is obtained through transthoracic impedance values in the implanted device. We investigated the correlation between Optivol status and T wave alternans status.
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Complete list of historical versions of study NCT00669682 on ClinicalTrials.gov Archive Site
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T-wave Alternans and Intrathoracic Impedance Measurements
T-wave Alternans and Intrathoracic Impedance Measurements

T-wave alternans is a test that is currently being used to risk stratify patients with structural heart disease for sudden cardiac death. The mechanism of T-wave alternans is unclear, but may share a common abnormality with conditions of cardiac fluid overload such as heart failure, which is altered intracellular calcium handling. Current Medtronic implantable defibrillators have the capability of monitoring cardiac fluid status via transthoracic impedance measurements.

The purpose of this study is to determine if a correlation exists between T-wave alternans status and cardiac volume status, as determined by transthoracic impedance measurements. Secondarily, the study seeks to examine the relationship between arrhythmia frequency and T-wave alternans or cardiac volume status.

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Observational Model: Cohort
Time Perspective: Prospective
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Non-Probability Sample
Class III or IV heart failure patients
  • Congestive Heart Failure
  • Arrhythmias
Other: Congestive heart failure
Spontaneous occurrence of fluid overload.
Group A
The study group will include Class III to IV heart failure patients followed in the device clinic that have a chronically implanted (more than 90 days) Medtronic biventricular defibrillator with the ability to monitor intrathoracic impedance.
Intervention: Other: Congestive heart failure
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
April 2012
April 2012   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • Class III or IV heart failure patients with a chronically implanted Medtronic biventricular defibrillator system capable of monitoring intrathoracic fluid volume.

Exclusion Criteria:

  • no active ischemia or pulmonary edema, atrial fibrillation, complete heart block
Sexes Eligible for Study: All
18 Years and older   (Adult, Senior)
Contact information is only displayed when the study is recruiting subjects
United States
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Jose M. Dizon, Columbia University
Columbia University
Principal Investigator: Jose M Dizon, MD Columbia University
Columbia University
April 2013