Syncope.

Syncope is a common clinical presentation. Although most commonly benign, it may herald a pathology with a poor prognosis. The work-up of syncope includes a careful history, physical examination, electrocardiogram, risk stratification, and appropriately directed testing. The key factor in the investigation of syncope is the presence (or absence) of structural heart disease or an abnormal electrocardiogram. The most useful investigation in unexplained syncope with a normal heart is the tilt table test for evaluating predisposition to neurocardiogenic (vasovagal) syncope. In the setting of structural heart disease or an abnormal electrocardiogram, electrophysiologic studies play a more important role. The utility of noninvasive cardiac monitoring for symptom-rhythm correlation may be limited by infrequent symptoms. The availability of external and implantable loop recorders allows prolonged periods of monitoring to increase diagnostic yield. The management of patients with syncope may be complex. Early referral to a cardiac electrophysiologist is warranted in patients who are at high risk.