T-wave Alternans and Intrathoracic Impedance Measurements

Completed

• Conditions: Congestive Heart Failure; Arrhythmias
• Interventions: Other: Congestive heart failure

• Registration Number: NCT00669682
• Lead Sponsor: 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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2008-04-28
• Study First Submitted QC: 2008-04-29
• Study First Posted: 2008-04-30
• Study Start: 2008-08
• Primary Completion: 2012-04
• Study Completion: 2012-04
• Results First Submitted: 2013-02-15
• Results First Submitted QC: 2013-02-15
• Results First Posted: 2013-03-28
• Status Verified: 2013-04
• Last Update Submitted: 2013-04-11
• Last Update Posted: 2013-04-19

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 9

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

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Group A	Congestive heart failure	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.

Primary Outcome Measures

Name	Time	Method
Number of Positive Twave Studies and Concurrent Positive Optivol Measurement	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.

Trial Locations

Locations (1)

Columbia University Medical Center; 🇺🇸 New York, New York, United States