Role of echocardiography in diagnostic evaluation of patients admitted to observation unit

Syncope is a transient loss of consciousness due to transient decrease in cerebral perfusion. Syncope accounts for a 3-6% of all emergency department visits. Etiology of syncope can be neural, cardiogenic, or vascular. Previous studies have evaluated the types and management of syncope. Echocardiography is a commonly used test in the evaluation of causes of syncope. Whether the benefit compared to financial burden of this diagnostic study is in all subsets of syncope cases remains unclear.

To evaluate the impact of echocardiography in the diagnostic evaluation of syncope and to evaluate the subset of patients that would benefit more from this diagnostic imaging.

We performed a retrospective chart review of patients > 18 years of age with a primary diagnosis of syncope in a period of January 1^st 2015-January 31^st 2017. Our inclusion criteria included patients > 18 years of age who were admitted to the observation floor with the primary complaint as syncope, had a normal or abnormal physical examination for syncope, had a normal or abnormal electrocardiogram during admission, had an echocardiography performed at admission. Our exclusion criteria included patients with seizures, hypoglycemia, myocardial infarction, patients who didn't get echocardiography, and patients who had a positive marker of cardiac injury.

A total of 369 patients were initially identified with a primary diagnosis of syncope, however only 120 of these patients fulfilled our inclusion and exclusion criteria. A total of n=25 of included patients had either an abnormal physical exam or abnormal echocardiography. Among this "high risk" group, 24% (n=6) of the patients had an abnormal finding on their transthoracic echocardiography. On the other hand, in the "low risk" group with a normal physical examination and electrocardiogram (EKG), 14 had a trans-thoracic echocardiography (TTE) positive for cause of syncope, that led to a change in medication, workup, or intervention in 6.7% (n=8) of the patients.

The analysis of our study suggested that the diagnostic yield of transthoracic echocardiography in syncope is very limited in the absence of an abnormal physical exam or electrocardiogram, and it increase the health care cost burden with no additional benefits.