Since the development of coronary care units (CCUs), telemetry has rapidly become the standard of care in evaluating patients with suspected acute coronary syndromes, regardless of the probability for ischemia. However, there is no data to support this practice. Our objective was to evaluate the utility of routine cardiac monitoring in a chest pain observation unit. We prospectively studied the utility of routine cardiac monitoring in 249 consecutive patients admitted to an observation unit in an academic Emergency Department over a 6-month period. All the patients presented with chest pain thought to be cardiac ischemia. Observation included serial cardiac enzymes, ECG cardiac monitoring, and exercise testing in a designated chest pain observation unit. These patients were determined to be at low risk for an acute coronary event by two criteria: first, the symptoms had resolved by the time of observation unit admission, and second, the initial ECG was normal, unchanged or non-diagnostic for acute ischemia. Adverse outcomes included cardiac arrest, hospital admission secondary to cardiac dysrhythmia, or alteration in the patient's medical therapy upon discharge from the observation unit, secondary to cardiac dysrhythmia. There were 249 patients included with a median age of 52 with 60% women. Fifteen percent of the patients were, subsequently, admitted to the hospital for further evaluation of ischemia based on enzyme, ECG, and exercise testing results. One patient with known Tachy-Brady syndrome was noted to have 1.5-2 s pauses while sleeping, and discharged with instructions to hold beta blocker therapy pending results of a continuous loop recorder. Of the remaining 248 patients, no patient suffered a cardiac arrest, no patient was admitted to the hospital secondary to cardiac dysrhythmia, and no alteration in a patient's medical therapy was made secondary to cardiac dysrhythmia. No patient returned to the Emergency Department within 72 h with cardiac arrest, acute dysrhythmia or acute myocardial infarction. Although telemetry may be the standard of care in evaluating the patients with suspected acute coronary syndromes, regardless of the probability of an acute ischemic syndrome, in those patients with a normal or non diagnostic ECG and resolved symptoms, routine cardiac monitoring is unnecessary.