Sudden cardiac death (SCD) is one of the most critical public health problem causing 20-30% of 0.4 million annual deaths due to heart disease in the United States. Among these, ventricular fibrillation is observed in 85% of the cases before death. Prognostic significance of microvolt T-wave alternans (TWA) has been established since their inclusion among important risk stratifiers for sudden cardiac death, as they provide a 20-30 minutes warning period prior to ventricular tachyarrhythmias. This book reviews the most significant TWA analysis schemes belonging to STFT, sign-change counting and non-linear filtering domains. The main objective is to develop robust TWA detection and estimation schemes. A second direction is to explore the estimation challenges involved in TWA analysis.