T Wave Alternans in Congestive Heart Failure - TWA in CHF

Jun 02, 2003
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Date Presented:
01/01/2003
Date Updated:
06/02/2003
Original Posted Date:
06/02/2003
References

Description:

The goal of the T Wave Alternans in Congestive Heart Failure (TWA in CHF) study was to determine if TWA is associated with an increased risk of having an arrhythmic event in patients with left ventricular (LV) dysfunction who have not yet had an arrhythmic event.

Hypothesis:

TWA is associated with an increased risk of having an arrhythmic event in patients with LV dysfunction who have not yet had an arrhythmic event.

Study Design

Study Design:

Patients Screened: 590
Patients Enrolled: 542
NYHA Class: NYHA II (52%) and III (28%)
Mean Follow Up: Mean follow-up to date 12.2 months
Mean Patient Age: Mean age 56 years
Female: 29
Mean Ejection Fraction: Mean EF was 0.25 ± 0.9 and 61% of patients had an EF <30%.

Patient Populations:

EF ≤40% with no prior history of an arrhythmic event and age ≥18 years

Exclusions:

Unstable coronary disease, New York Heart Association (NYHA) class IV CHF, and persistent atrial arrhythmias

Primary Endpoints:

Arrhythmic death and nonfatal cardiac arrest.

Secondary Endpoints:

All-cause mortality

Drug/Procedures Used:

Patients with LV dysfunction who have not yet had an arrhythmic event underwent exercise testing with TWA and a 24-hour Holter recording.

Principal Findings:

The TWA test was positive in 30%, negative in 34%, and indeterminate in the remaining 36%. All-cause mortality at two years was higher in TWA positive patients versus TWA negative patients (hazard ratio [HR] 9.7, log rank p<0.01).

Among patients who were TWA negative and had an ejection fraction (EF) <30% (n=78), only one death occurred during follow-up. In a model adjusting for EF, positive TWA remained associated with mortality (HR 8.4, p<0.01).

Interpretation:

Among patients with LV dysfunction who have not yet had an arrhythmic event, TWA was associated with an increased risk of death. TWA may provide additional risk stratification for patients with a low EF who, despite a low EF, may have low mortality and little benefit from an implantable cardioverter defibrillator (ICD).

Given the high cost of ICDs, risk stratification methods will be valuable in identifying an optimal patient population for use of the therapy. Further follow-up is needed to determine if the TWA remains associated with long-term follow-up. Additionally, results of the primary end point of arrhythmic death and nonfatal cardiac arrest are pending.

References:

Presented at Late-Breaking Clinical Trials, ACC 2003.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure

Keywords: Follow-Up Studies, Heart Failure, Ventricular Dysfunction, Left, Defibrillators, Implantable, Exercise Test


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