(Level of Evidence: C) LV function is one of the strongest predictors of survival in patients with STEMI. LV function most commonly is evalu- ated with contrast ventriculography at the time of cardiac catheterization or with transthoracic echocardiography on day 2 or 3. Echocardiography is the most frequently used imag- ing modality to evaluate regional and global LV function after STEMI and can help characterize any associated mechanical complications when they are clinically suspected. Because of the dynamic nature of LV functional recovery after STEMI, clinicians should consider the timing of the imaging study relative to the index event. In patients with significant LV sys- tolic dysfunction revealed during the initial hospitalization, LV function should be reevaluated 40 days later, especially to address the potential need for ICD therapy after allowance for recovery from myocardial stunning.496,587,588 10.3. Assessment of Risk for SCD: Recommendation Class I 1. Patients with an initially reduced LVEF who are possible candidates for ICD therapy should under- go reevaluation of LVEF 40 or more days after dis- (Level of Evidence: B) The timing and character of ventricular arrhythmias and resid- ual LV systolic function are the strongest predictors of SCD risk after STEMI. Management considerations for patients with ventricular arrhythmias during the hospital phase are reviewed in Section 9.5. Hospital survivors with an initially reduced LVEF ( 0.40) who do not merit ICD therapy before discharge should undergo reassessment of LV function 40 days later to determine their eligibility for ICD therapy. The recommended delay to ICD therapy in this setting stems from the results of DINAMIT (Defibrillator in Acute Myocardial Infarction Trial), in which defibrillator implantation 6 to 40 days after MI in patients with EF 0.35 and impaired cardiac autonomic function was not shown to reduce overall cardiac death risk. 