Heart Rate Variability (HRV) Testing Compared With Exercise Stress Test in Hospitalized Patients With Chest Pain

There are many patients hospitalized for chest pain, which don\'t have high risk features that require invasive coronary angiography, but are considered intermediate risk and for which ischemic heart disease can not be excluded. The current management for these patients is to perform a non invasive test in order to classify their risk. Exercise ergometry is a commonly used non invasive test to detect ischemia. that test is non-invasive, and does not involve radiation or intra-venous contrast. The test is limited for many patients, because of un-ability to exercise, or because of non-interpetable Electro Cardio-Graphy (ECG). Heart rate variability is well known to be a marker of ischemic heart disease. Heart rate variability testing is a non-invasive ECG monitoring technique. The study design is to identify hospitalized patients who are candidates for non-invasive stress testing, and to monitor their heart rate variability for one hour prior to the stress test.