Cardiac monitoring is used for diagnosing patient with symptoms. Holter monitoring or cardiac loop monitoring are the tests most ofter prescribed for patients depending on the frequency of symptoms. If the symptoms occur daily, a Holter may be prescribed, but when the symptoms become less frequent the diagnostic yield of Holter monitoring declines greatly. The current yields are approximately 5-10% depending on the indication. When the Holter is not longer an option for patients with infrequent symptoms a cardiac loop event monitor is prescribed to make a diagnosis. The yields on this monitoring also average approximately 25-35%. We feel that the yield on the Mobile Cardiac Ouptatient Telemetry (MCOT) service proviced by CardioNet is significantly higher due to the fact that every beat is analyzed using an algorithm and that many times the arrhythmia causing the symptoms has ended before the patient is able to press the button on the loop monitor to record the ECG. This study compares the MCOT service with Patients over 18 years of age experiencing syncope, near syncope or palpitations less frequently than daily. Require 24 hours of non-diagnostic ECG monitoring prior to randomization. Patients remain on monitoring for 30 days unless an arrhythmia diagnosis is made. The primary endpoint is confirmation of exclusion of a probable arrhythmic cause of pre-syncope, syncope or palpitations experienced by the subject prior to enrollment in the study. Secondary endpoints include time to diagnosis, time to detection of clinically significant arrhythmias, comparison of non-clinicaly significant arrhythmias, rate of asymptomatic arrhythmias both clinically and non clinically significant and a diagnosis related resource utilization. The study size is 300 subjects.