T-wave Alternans and Intrathoracic Impedance Measurements

This study has been completed.
Information provided by (Responsible Party):
Jose M. Dizon, Columbia University
ClinicalTrials.gov Identifier:
First received: April 28, 2008
Last updated: April 11, 2013
Last verified: April 2013

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 Intervention
Congestive Heart Failure
Other: Congestive heart failure

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: T-wave Alternans and Intrathoracic Impedance Measurements

Resource links provided by NLM:

Further study details as provided by Columbia University:

Primary Outcome Measures:
  • Number of Positive Twave Studies and Concurrent Positive Optivol Measurement [ Time Frame: upto 3 years ] [ Designated as safety issue: No ]
    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.

Enrollment: 9
Study Start Date: August 2008
Study Completion Date: April 2012
Primary Completion Date: April 2012 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
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.


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
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
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Please refer to this study by its ClinicalTrials.gov identifier: 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
  More Information

Responsible Party: Jose M. Dizon, Assoc Professor of Clinical, Department of Cardiology, Columbia University
ClinicalTrials.gov Identifier: NCT00669682     History of Changes
Other Study ID Numbers: AAAC5529 
Study First Received: April 28, 2008
Results First Received: February 15, 2013
Last Updated: April 11, 2013
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Heart Failure
Cardiovascular Diseases
Heart Diseases

ClinicalTrials.gov processed this record on April 27, 2016