Syncope is a sudden and transient episode of complete loss of consciousness with spontaneous recovery caused by a brief interruption of cerebral oxygen supply. Syncope is a common complaint in the emergency room, and during the initial evaluation, the cause often remains unclear. Initial approach should focus on risk stratification to determine if the patient requires in-hospital treatment and workup or outpatient treatment. Syncope classification included neutrally mediated, secondary to orthostatic hypotension, and cardiac. Cardiac syncope can be life-threatening. Risk factors for cardiovascular syncope include antihypertensive or antiarrhythmic drugs, family history of sudden cardiac death at a young age (<40 years), and family or personal history of cardiomyopathy or channelopathy. The main pathophysiologic characteristics are hypotension and concomitant cerebral hypoperfusion. There are two cardiac causes: arrhythmias and structural heart disease. In patients with cardiac syncope, the presence of premonitory symptoms like lightheadedness, sweating, palpitations, nausea, or visual blurring is not common. Syncope could be the clinical presentation of low-risk, submassive, or massive PE patients. Thus, assessment of risk factor, a complete clinical history, and information given by eyewitnesses become very valuable. Furthermore, the physical examination should include a complete neurological examination, blood pressure measurements, carotid sinus massage, and careful auscultation with special attention in murmurs, evaluation of pulses, and an electrocardiogram. Depending on the findings, we have high-, intermediate-, or low-risk patients which will help the physician to decide if the patient requires inpatient or outpatient evaluation.
