Cardiac evaluation for structural abnormalities may not be required in patients presenting with syncope and a normal ECG result in an observation unit setting

Study objective: Patients with syncope are frequently managed in observation units and receive serial examinations, monitoring for arrhythmias, and structural analysis of the heart. The primary aim of this study is to determine the utility of structural analysis of the heart in syncope patients who are being managed in an observation unit and have a normal ECG result.

Methods: This is a retrospective, observational chart review of all consecutive adult patients observed during 18 months at an urban, academic medical center. A case report form with demographics, ECG interpretations, and structural analysis of the heart data was generated and all variables were defined before data extraction. Subjects with an ECG demonstrating any arrhythmia, premature atrial contraction, premature ventricular contraction, pacing, second- and third-degree blocks, and left bundle branch block were excluded from the normal ECG group. An abnormal cardiac structure was defined as an ejection fraction less than 45%, severe hypertrophy, or severe valvular abnormality. Ten percent of cases were evaluated by a second extractor to verify accuracy. Descriptive statistics with confidence intervals (CIs) and interquartile ranges (IQRs; 25%, 75%) are used.

Results: Three hundred twenty-three subjects were managed in the observation unit for syncope, 48% were men, and their median age was 66 years (25%, 75% IQR 52, 80). Two of 323 (0.6%; 95% CI 0.2% to 2.2%) had an arrhythmia; 1 of 323 had a non-ST-segment myocardial infarction (0.3%; 95% CI 0.1% to 1.7%). Of the 323 patients, 267 had a normal ECG result and 235 (88%) had their cardiac structure evaluated. Forty-eight percent of the normal ECG group were men, and the median age was 65 years (25%, 75% IQR 52, 79). Zero of 235 patients (0%; 95% CI 0% to 1.6%) had a structural abnormality identified on evaluation, and 2 of 18 (11%; 95% CI 3.1% to 32.8%) had an abnormal stress echocardiogram result.

Conclusion: Structural abnormalities are unlikely in syncope patients with a normal ECG result. Care should focus on excluding arrhythmias and acute coronary syndrome.