Korean Circ J.  2005 Aug;35(8):597-604. 10.4070/kcj.2005.35.8.597.

Efficacy of T-Wave Alternans for the Prediction of Lethal Arrhythmic Events after Myocardial Infarction

• Hwang GS
• Jun DG
• Choi UJ
• Yoo SY
• Ahn SG
• Choi JH
• Choi BJ
• Zhen ZG
• Choi TY
• Choi SY
• Yoon MH
• Shin JH
• Tahk SJ

• KMID: 2093946
• DOI: http://doi.org/10.4070/kcj.2005.35.8.597

Abstract

BACKGROUND AND OBJECTIVES
The prevention of sudden death in patients with a myocardial infarction (MI) remains the therapeutic target. T-wave alternans is as a heart rate dependent measure of repolarization, which correlates with ventricular arrhythmia vulnerability. The goals of this study were to clarify whether microvolt-level T-wave alternans (mTWA) can predict lethal arrhythmic events, and compare their role with other risk indices in predicting lethal events following a MI.
SUBJECTS AND METHODS
The mTWA was analyzed in 78 MI patients, using a power-spectral method during bicycle exercise testing. Additionally, the left ventricular ejection fraction (EF), late potentials (LP) and heart rate variability were also measured.
RESULTS
The mTWA was positive in 16 patients (21%), negative in 36 (46%) and indeterminate in 21 (33%). Lethal arrhythmic events developed in 7 patients (3 sudden deaths, 3 ventricular tachycardia and 1 ventricular fibrillation), during a mean follow-up of 12+/-3 months. The event rate was significantly higher in patients with a positive mTWA (relative risk 12.0, 95% CI 1.2 to 118.1, p=0.01) or lower EF (<40%)(relative risk 11.0, CI 1.9 to 65.0, p=0.002). The mTWA test exhibited the highest sensitivity, relative risk and negative predictive value, but the lowest specificity; positive predictive values were observed compared with the EF or a combination of the two indices.
CONCLUSION
mTWA was closely related to the occurrence of lethal arrhythmic events in patients with a MI. Therefore, mTWA with a lower EF could be a useful screening test for the prediction of potentially lethal arrhythmic events following a MI.

Keyword

Myocardial infarction; Sudden cardiac death; Tachycardia, ventricular; Ventricular fibrillation

MeSH Terms

Arrhythmias, Cardiac
Death, Sudden
Death, Sudden, Cardiac
Exercise Test
Follow-Up Studies
Heart Rate
Humans
Mass Screening
Myocardial Infarction*
Sensitivity and Specificity
Stroke Volume
Tachycardia, Ventricular
Ventricular Fibrillation