There is a large body of evidence that presence of cardiac autonomic dysfunction after MI is associated with an increased susceptibility to malignant brady- and tachyarrhythmias eventually culminating in SCD. Periodic repolarization dynamics (PRD) and heart rate deceleration capacity (DC) are clinically validated autonomic risk markers that provide strong and independent prognostic information in post-MI patients with LVEF >35%. PRD and DC reflect different facets of autonomic function and can therefore be used in combination to predict risk. Previous studies demonstrated that combined assessment of PRD and DC identifies a new high-risk group among post-MI patients with moderately reduced LVEF (36-50%). This new high-risk group has similar characteristics with respect to prognosis and patient numbers as the established high-risk group identified by LVEF ≤35%.