Visual estimation of ejection fraction by two-dimensional echocardiography: the learning curve.

Our purpose was to determine the learning curve of visual estimation of ejection fraction (EF) by echocardiography. Sixty consecutive patients, who had clinically indicated echocardiography and radionuclide ventriculography (RVG) within 1 month were selected. Five standard views were reviewed independently by a first-year cardiology fellow, a private cardiologist, and an experienced echocardiographer. Observers were given feedback of the RVG EFs immediately after estimating the EF on each study. To assess the effect of learning, the echocardiographic studies were divided into three groups of 20 and were read successively by each observer. A statistical comparison of the two methods was performed for each group. The correlation between the two techniques for the first group of studies was marginal. There was a significant improvement in the correlation with subsequent groups. The correlation did not change significantly with the last group of studies compared with the second group. In conclusion, visual estimation of EF by two-dimensional echocardiography can be learned, with a learning curve of approximately 20 studies if immediate feed-back is available.