Diagnostic evaluation
When a patient presents with transient loss of consciousness (T-LOC), the history, usually initially derived from a general practitioner or ambulance personnel, is most important to determine whether it is indeed T-LOC. If so, more history taking is of paramount importance to differentiate between the different forms of T-LOC: syncope, epileptic seizures, or psychogenic attacks. When T-LOC is syncope and epileptic seizures and psychogenic attacks are less likely, the initial syncope evaluation should address the different forms of syncope: reflex syncope, orthostatic hypotension, or cardiac syncope. The initial syncope evaluation consists of (1) more detailed and careful history taking, (2) a physical examination, including supine and standing blood pressure measurements, and (3) an electrocardiogram. When the initial syncope evaluation does not yield either a certain or a highly likely diagnosis, the next step is to perform risk stratification of major cardiovascular events including sudden death. The subsequent evaluation will be determined by the causal risk.