Reproducibility of echocardiographic left ventricular measurements.

Serial echocardiograms with acceptable reproducibility of measurements may be produced by careful performance and interpretation of the studies. The following recommendations have been shown to enhance reproducibility. Strict adherence to quality control is necessary to generate echocardiograms of the highest technical quality. Sonographers should be aware of the definition of a technically adequate study--including correct beam or plane angulation and continuous visualization of interfaces--and seek this ideal in every study. Participation by the sonographer in performance of measurements enhances recognition of the requirements for accurate quantitative echocardiography. Regular machine calibration is a prerequisite to accurate quantitative echocardiography. Considerable effort must be made to standardize the position of each acoustic window and angulation from which the patient is imaged--with deviation from these norms being recorded for future reference. If at all possible, measurements should be taken at end expiration. If that is not possible, measurement of several consecutive beats will limit the impact of respiratory variation. A uniform convention of measurement should be adopted. The best candidates for M-mode measurements are the American Society of Echocardiography recommendations for general measurement and the Penn convention for calculation of M-mode left ventricular mass. Further data is needed to determine which approaches to two-dimensional measurements best combine accuracy and reproducibility. Interpretation of echocardiograms may be made most reproducible by measuring pertinent parameters from multiple beats and using the mean as the result and by having at least two readers interpret each echocardiogram, possibly with two separate readings by each reader.