1. Macroscopic T-wave alternans describes beat-to-beat fluctuations of T-wave amplitude visible on electrocardiogram suggesting high risk or susceptibility for life-threatening ventricular arrhythmias. Microvolt changes in T-wave alternans, imperceptible to naked-eye ECG evaluation, can be analyzed using proprietary software, and can be associated with risk for arrhythmic sudden cardiac death, and therefore can be useful in identifying patients with congestive heart failure who may benefit from an implantable cardioverter defibrillator.
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