Identification of patients who are at highest risk for heart attack is an important task for emergency medicine physicians. Currently, physicians use a variety of different scoring systems to stratify their risk for having a heart attack. Heart rate variability (HRV) is a measure derived from noninvasive cardiac monitoring. This data is collected from a simple, non-invasive chest strap during a 10-minute recording session. The purpose of this proposal is to collect heart rate variability data on patients admitted to the emergency department with chest pain. The intent is to measure the association between heart rate variability and the various risk stratification scoring systems for chest pain.