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CLINICAL GUIDELINE: Diagnosing Syncope: Part 2: Unexplained Syncope

Mark Linzer, MD; Eric H. Yang, BS; N.A. Mark Estes III, MD; Paul Wang, MD; Vicken R. Vorperian, MD; and Wishwa N. Kapoor, MD, MPH
[+] Article, Author, and Disclosure Information

For the Clinical Efficacy Assessment Project of the American College of Physicians* From University of Wisconsin School of Medicine, Madison, Wisconsin; New England Medical Center, Boston, Massachusetts; and University of Pittsburgh, Pittsburgh, Pennsylvania. *For members of the Clinical Efficacy Assessment Project, see the Appendix. Note: The Clinical Efficacy Assessment Project (CEAP) of the American College of Physicians is designed to evaluate and inform College members and others about the safety and efficacy of diagnostic and therapeutic methods. Acknowledgments: The authors thank Dr. Edward L.C. Pritchett for his comments on the cardiologic sections of the manuscript; Dr. Benjamin Eidelman for his comments on the neurologic sections; Dr. David Katz for his comments on an earlier version of the manuscript; Thomas Havighurst, MS, for statistical analysis; and Cindy Gilles for secretarial assistance. Requests for Reprints: Mark Linzer, MD, University of Wisconsin School of Medicine, Department of Medicine, J5/210 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792-2454. Current Author Addresses: Dr. Linzer: University of Wisconsin School of Medicine, Department of Medicine, J5/210 Clinical Science Center, 600 Highland Avenue, Madison, WI 53792-2454.

Copyright ©2004 by the American College of Physicians

Ann Intern Med. 1997;127(1):76-86. doi:10.7326/0003-4819-127-1-199707010-00014
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Purpose: To review the literature on diagnostic testing in syncope that remains unexplained after initial clinical assessment.

Data Sources: MEDLINE search.

Study Selection: Published papers were selected if they addressed diagnostic testing in syncope, near syncope, or dizziness.

Data Extraction: Studies were identified as population studies, referral studies, or case series.

Data Synthesis: After a thorough history, physical examination, and electrocardiography, the cause of syncope remains undiagnosed in 50% of patients. In such patients, information may be derived from the results of carefully selected diagnostic tests, especially 1) electrophysiologic studies in patients with organic heart disease, 2) Holter monitoring or telemetry in patients known to have or suspected of having heart disease, 3) loop monitoring in patients with frequent events and normal hearts, 4) psychiatric evaluation in patients with frequent events and no injury, and 5) tilt-table testing in patients who have infrequent events or in whom vasovagal syncope is suspected. Hospitalization is indicated for high-risk patients, especially those with known heart disease and elderly patients.

Conclusions: A flexible, focused approach is required to diagnose syncope. Features of the initial history and physical examination help guide diagnostic testing.


Grahic Jump Location
Figure 1.
Algorithm for diagnosing syncope.

* Carotid massage can be performed in an office setting only in the absence of bruits, a history of ventricular tachycardia, recent stroke, or recent myocardial infarction. Carotid hypersensitivity should be diagnosed only if clinical history is suggestive and massage is diagnostically positive (asystole ≥ 3 seconds, hypertension, or both). † May be replaced by inpatient telemetry if there is concern about serious arrhythmia. OHD = organic heart disease.

Grahic Jump Location




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