[Microvolt level T wave alternans: a new marker for noninvasive risk stratification]

Area of Science:

• Cardiology
• Electrophysiology
• Biomedical Engineering

Background:

• Identifying patients with structural heart disease who benefit from prophylactic implantable cardioverter-defibrillator (ICD) therapy is challenging due to limitations in current risk stratification methods.
• Impaired ventricular repolarization is linked to increased ventricular tachyarrhythmias, suggesting a potential marker for risk assessment.

Purpose of the Study:

• To evaluate microvolt T wave alternans (TWA) as a novel, noninvasive parameter for risk stratification in patients with structural heart disease.
• To assess the predictive value of TWA for future tachyarrhythmic events and appropriate ICD therapy.

Main Methods:

• Noninvasive measurement of T wave alternans, a marker of ventricular repolarization, using exercise stress testing to induce alternans.
• Prospective evaluation in patients who survived prehospital ventricular fibrillation or sustained ventricular tachycardia.

Main Results:

• T wave alternans measurement demonstrated a good concordance with invasive assessments.
• Noninvasive TWA assessment during submaximal exercise testing was predictive of future tachyarrhythmic events in high-risk patients.
• Occurrence of T wave alternans predicted the need for appropriate ICD therapy.

Conclusions:

• Noninvasive microvolt T wave alternans testing is a promising tool for risk stratification in patients with structural heart disease.
• TWA assessment may enhance the identification of patients who would benefit from prophylactic ICD therapy, improving clinical practice.