Diagnosis of Syncope

A systematic review 1 included 12 studies.

There is no diagnostic gold standard for syncope. First, history, physical examination, and electrocardiography are the core of the diagnostic workup, providing a combined diagnostic yield of 50%. Second, neurological testing is rarely helpful unless additional neurological signs and symptoms are present (diagnostic yield of EEG, CT, and Doppler ulrasonography, 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, coronary angiography or intracardiac electrophysiological studies, alone or in combination (diagnostic yields, 5% to 30%). Fourth, tilt testing (diagnostic yield as high as 60%) and/or long-term loop electrocardiography (diagnostic yield, 25% to 35%) and tilt testing (diagnostic yield as high as 60%) are most useful in patients with recurrent syncope in whom heart disease is not suspected. Fifth, psychiatric evaluation can detect mental disorders associated with syncope in up to 25% of cases.

A prospective cohort study 2 included 101 suspected (pre) syncope patients and compared usual evaluation in the emergency department with standardised evaluation according to the ESC syncope guidelines 3. Diagnostic accuracy (proportion of correct diagnoses) was determined by expert consensus after long-term follow-up.Usual practice of the initial treating physician resulted in a diagnostic accuracy of 65%, while standardised practice, with an emphasis on thorough history taking, increased diagnostic accuracy to 80%.

Comment: The validity of the primary studies is not discussed, and the review relies on referral studies and case series.

The following decision support rules contain links to this evidence summary:

• ECG in patients with syncope http://www.ebmeds.org/ebmeds/ebmeds_home.asp?mode=scripts&submode=view&id=scr00474&country=UK

References

• Linzer M, Yang EH, Estes NA 3rd, Wang P, Vorperian VR, Kapoor WN. Diagnosing syncope. Part 1: Value of history, physical examination, and electrocardiography. Clinical Efficacy Assessment Project of the American College of Physicians. Ann Intern Med 1997 Jun 15;126(12):989-96. [PubMed]
• van Wijnen VK, Gans ROB, Wieling W et al. Diagnostic accuracy of evaluation of suspected syncope in the emergency department: usual practice vs. ESC guidelines. BMC Emerg Med 2020;20(1):59. [PubMed]
• Brignole M, Moya A, de Lange FJ et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018;39(21):1883-1948. [PubMed]