T-Wave Alternans as an Arrhythmic Risk Stratifier: State of the Art

• Authors: Faisal Merchant, Emory University; Omid Sayadi, Massachusetts General Hospital; Kasra Moazzami, Massachusetts General Hospital; Dheeraj Puppala, Massachusetts General Hospital; Antonis A. Armoundas, Massachusetts General Hospital
• Journal Title: Current Cardiology Reports
• Volume: Volume 15, Number 9
• Publisher: Springer (part of Springer Nature): Springer Open Choice Hybrid Journals | 2013-09-01, Pages 398-398
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1007/s11886-013-0398-7
• Subjects: Health Sciences, Medicine and Surgery
• Keywords: Science & Technology; Life Sciences & Biomedicine; Cardiac & Cardiovascular Systems; Cardiovascular System & Cardiology; Repolarization alternans; Arrhythmia risk stratification; Arrhythmia prevention; Sudden cardiac death; T-wave alternans; IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR; SUDDEN CARDIAC DEATH; CALCIUM TRANSIENT ALTERNANS; ACTION-POTENTIALS; VENTRICULAR TACHYARRHYTHMIAS; INTRACELLULAR CALCIUM; ELECTRICAL ALTERNANS; MECHANICAL ALTERNANS; CONTRACTILITY MODULATION; ISCHEMIC CARDIOMYOPATHY

Abstract

Microvolt level T-wave alternans (MTWA), a phenomenon of beat-to-beat variability in the repolarization phase of the ventricles, has been closely associated with an increased risk of ventricular tachyarrhythmic events (VTE) and sudden cardiac death (SCD) during medium- and long-term follow-up. Recent observations also suggest that heightened MTWA magnitude may be closely associated with short-term risk of impending VTE. At the subcellular and cellular level, perturbations in calcium transport processes likely play a primary role in the genesis of alternans, which then secondarily lead to alternans of action potential morphology and duration (APD). As such, MTWA may play a role not only in risk stratification but also more fundamentally in the pathogenesis of VTE. In this paper, we outline recent advances in understanding the pathogenesis of MTWA and also the utility of T-wave alternans testing for clinical risk stratification. We also highlight emerging clinical applications for MTWA.