T-wave Alternans and Intrathoracic Impedance Measurements

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. 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):
Jose M. Dizon, Columbia University

Brief Summary:

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.

Condition or disease Intervention/treatment
Congestive Heart Failure Arrhythmias Other: Congestive heart failure

Study Type : Observational
Actual Enrollment : 9 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: T-wave Alternans and Intrathoracic Impedance Measurements
Study Start Date : August 2008
Actual Primary Completion Date : April 2012
Actual Study Completion Date : April 2012

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Heart Failure

Group/Cohort Intervention/treatment
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.
Other: Congestive heart failure
Spontaneous occurrence of fluid overload.

Primary Outcome Measures :
  1. 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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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Class III or IV heart failure patients

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

Information from the National Library of Medicine

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 identifier (NCT number): NCT00669682

United States, New York
Columbia University Medical Center
New York, New York, United States, 10032
Sponsors and Collaborators
Columbia University
Principal Investigator: Jose M Dizon, MD Columbia University

Responsible Party: Jose M. Dizon, Assoc Professor of Clinical, Department of Cardiology, Columbia University Identifier: NCT00669682     History of Changes
Other Study ID Numbers: AAAC5529
First Posted: April 30, 2008    Key Record Dates
Results First Posted: March 28, 2013
Last Update Posted: April 19, 2013
Last Verified: April 2013

Additional relevant MeSH terms:
Heart Failure
Heart Diseases
Cardiovascular Diseases