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

AIMS: 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. METHODS AND RESULTS: 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. CONCLUSION: 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.