Heart rhythm abnormalities underlie one of the common presenting complaints to the A&E and out-patient departments, specifically awareness of heart beats or palpitations. Unless an ECG (electrocardiogram) tracing of the heart rhythm can be recorded while the patient is having symptoms, it is very difficult to determine the cause of the palpitations. The conventional approach is to refer these patients from the emergency departments to the Cardiology outpatients where they undergo repeated short term rhythm monitoring hoping to record the rhythm underlying the patient's complaint. Unfortunately, this often yields no results thus delaying definitive treatment and incurring extra costs of repeated investigations and A&E presentations. This study aims to compare the ability of the conventional approach to establish a definite diagnosis compared to that of an early invasive monitoring approach with a small implantable device that records the heart rhythm at all time for up to 18 months.