Ordering an echocardiogram for evaluation of left ventricular function: Level of expertise necessary for efficient use

This prospective study was performed to test the hypothesis that the yield of 2-dimensional echocardiography (2DE) would be higher when it is ordered by a cardiologist than by a noncardiologist. Patients referred for transtho racic 2DE for the evaluation of left ventricular systolic function for the 11-month period between July 10, 1995, and June 10, 1996, were included in the study. Demographic, historical, and clinical findings were recorded. Wh ether the patient was referred by a cardiologist versus a noncardiologist w as used as the predictor variable in a binary logistic regression analysis. To address the possibility that the yield of 2DE may be higher for cardiol ogists because the prevalence of disease in patients referred to them may b e higher (selection bias), the analysis was subjected to a propensity score adjustment. Of 2176 patients referred for 2DE during the study, 1033 were referred for the evaluation of left ventricular function. The test had a po sitive yield in 52% of patients for cardiologists versus 31% for noncardiol ogists (chi(2) = 45.5, P <.0001, odds ratio 2.4 [CI = 1.9-3.1]). This diffe rence remained highly significant even when propensity score risk adjustmen t was made (chi(2) = 54.2, P <.0001, odds ratio 2.0 [CI = 1.5-2.8]). We con clude that the yield of 2DE is higher for cardiologists compared with nonca rdiologists and that this result was not related to differences in patient populations examined by the two groups. Thus, more efficient use of 2DE may be achieved if patients are referred to cardiologists rather than directly sent for 2DE.