Differences Between Echocardiographic Measurements of Left Ventricular Dimensions and Function by Local Investigators and a Core Laboratory in a 2-year Follow-up Study of Patients with an Acute Myocardial Infarction

Abstract

To examine differences in measurements of left ventricular dimensions and function, and prognostic value between local investigators and a core laboratory in a multicentre serial echocardiographic study. Seven hundred and fifty-six patients with acute myocardial infarction and preserved left ventricular function were examined at baseline and after 3 months with measurements by the biplane Simpson's method, and followed prospectively from 3 to 24 months. At baseline and 3 months local investigators relative to the core laboratory measured lesser end-diastolic volume by 8 and 6 ml (P<0.001), end-systolic volume by 3 and 2 ml (P<0.01), and ejection fraction by 0.0 and 0.6% (P<0.01), respectively. Local investigators and the core laboratory measured an increase in left ventricular end-diastolic volume of 8.6 and 6.9 ml, and in left ventricular end-systolic volume of 5.2 and 4.3 ml, and a decrease in left ventricular ejection fraction of 0.6 and 0.0%. Using the Cox proportionate hazards model, the prognostic value for subsequent clinical endpoints was significant both for the 3-month values (P<0.05) and changes (P<0.005) measured by the core laboratory, but not by local investigators. Only measurements in the core laboratory had significant prognostic value for subsequent clinical endpoints. These results strongly support the use of a core laboratory in studies employing echocardiographic measurements.