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Despite the absence of a diagnostic gold standard and the paucity of data from randomized trials,several points emerge.First,history,physical examination,and electrocardiography are the core of the syncope workup (combined diagnostic yield,50%).Second,neurologic testing is rarely helpful unless additional neurologic signs or symptoms are present (diagnostic yield of electroencephalography,computed tomography,and DOppler ultrasonography,2%to 6%).Third,patients in whom heart disease is known or suspected or those with exertional syncope are at higher risk for adverse outcomes and should have cardiac testing,including echocardiography,stress testing,Holter monitoring,,or intracardiac electrophysiologic studies,alone or in combination(diagnostic yields,5%to 35%).Fourth,syncope in the elderly often results from polypharmacy and abnormal physiologic responses to daily events.Fifth,long-term loop electrocardiography(diagnostic yield,25%to 35%)and tilt testing(diagnostic yield70 years)or with acute neurologic signs.Many tests for syncope have a low diagnostic yield.A careful history,physical examination,and electrocardiography will provide a diagnosis or determine whether diagnostic testing is necessary in most patients. |
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