Echocardiography in the evaluation of patients with syncope.

OBJECTIVE: Echocardiography is frequently used as a screening test for cardiac disease in patients with syncope despite the lack of published data describing its utility in this regard. The goal of the study was to examine the frequency with which echocardiography was used in the evaluation of patients admitted to one medical center because of syncope and to examine the diagnostic information, over and above that provided by the initial history, physical examination, and electrocardiography, contributed by the echocardiogram.
DESIGN: A retrospective review was performed of all patients admitted to the study institution because of syncope over a seven-month period.
SETTING: University teaching hospital in an urban setting of 2.5 million population. PATIENTS/PARTICIPANTS: One hundred twenty-eight patients were identified: 47 men and 81 women (average age 67 +/- 17 years). Patients for whom syncope was of a known cause, those with near-syncope or vertigo, those with clinically obvious seizure, or those referred for electrophysiologic testing were excluded, leaving 128 patients for analysis. Details from the admission history, physical examination, and electrocardiography for each patient were recorded. The results of all other diagnostic tests ordered to evaluate syncope were recorded along with any consultations obtained. The cause of syncope was assigned by examining all physicians' notes and test results and with the use of previously published diagnostic criteria as guidelines.
MEASUREMENTS AND MAIN RESULTS: Ninety percent of the patients underwent cardiac testing other than routine electrocardiography and continuous telemetry monitoring while in the hospital. An echocardiogram was obtained for 64% of the patients and did not reveal an unsuspected cause for syncope in any case. The echocardiogram was normal for 52% of the patients undergoing the test. Echocardiograms of patients with syncope and no clinical evidence of heart disease by history, physical examination, or electrocardiography either were normal (63%) or provided no useful additional information for arriving at a diagnosis (37%). Nearly half (46%) of the patients undergoing echocardiography fit this clinical profile. Among the patients for whom cardiac disease was suspected after history, physical examination, or electrocardiography, the echocardiogram confirmed the suspected diagnosis for 48% and served to rule out a suspected diagnosis for the remaining 52%. In no instance did echocardiography provide an unsuspected cause for syncope. The history, physical examination, and initial electrocardiography provided sufficient information to permit a diagnosis to be made for 37 of the 48 patients (77%) for whom a cause of syncope was ultimately determined.
CONCLUSION: Echocardiography was frequently used in the evaluation of patients admitted to the hospital because of syncope of unclear cause. For patients without suspected cardiac disease after history, physical examination, and electrocardiography, the echocardiogram did not appear to provide additional useful information, suggesting that syncope alone may not be an indication for echocardiography. For patients with suspected heart disease, echocardiography served to confirm or refute the suspicious in equal proportions. These data provide an objective basis to prospectively define the optimal role of echocardiography in the evaluation of patients with syncope.