Validity of echocardiographic measurement in an epidemiological study - Project HeartBeat!

In Project HeartBeat!, a longitudinal study of cardiovascular disease risk factors in healthy children and adolescents, 3 samples of 40, 80, and 182 e chocardiograms, respectively, were randomly selected and reread to evaluate intraobserver and interobserver variabilities and comparability between me asurements of field echocardiographic technicians and reference readings at Texas Children's Hospital. Included in the evaluation were 8 M-mode echoca rdiographic measurements, ie, aortic root diameter, left atrial diameter, a nd end-diastolic and end-systolic measurements of interventricular septal t hickness, left ventricular (LV) diameter, and LV posterior wall thickness; 8 Doppler measurements: and a calculated LV mass. Means and SDs of the diff erences of the paired measurements were used to assess the relative bias an d random error of the measurements. For the intraobserver comparison, means and SDs of the differences were very small, indicating that the echo measu rements were performed consistently by each project echo technician. Intero bserver comparison showed statistically but not clinically significant diff erences between the paired readings of end-diastolic septal thickness, end- systolic LV posterior wall thickness, and 5 Doppler measurements. Compariso n with reference readings at Texas Children's Hospital showed significant d ifferences in diastolic LV diameter, systolic septal thickness, and right v entricular ejection time. These differences, however, were minimal with lim ited clinical significance. Mean differences in LV mass for the correspondi ng comparisons were -1.82, 4.50, and 0.0013 g, and the SDs were 18.79, 24.1 6, and 12.35 g, respectively. We conclude that the echocardiographic measur ements taken from healthy children in a longitudinal study can be made accu rately with acceptable reproductibility.