While noninvasive tests have been developed to estimate SCD risk, prior approaches have failed to: 1) identify the majority of patients at risk for serious arrhythmias (insensitive), 2) evaluate temporal changes in parameters, 3) identify the optimal timing for risk assessment post-MI, & 4) develop a widely-applicable screening tool. This has resulted in a failure to delivery effective therapies (e.g., defibrillator) in a cost-effective manner.