[Computer assisted determination of left-ventricular contraction abnormalities using two-dimensional echocardiography. I. Analysis various study methods and determination of normal values].
In 181 patients without signs of heart disease we determined the normal contraction pattern of the left ventricle in the echocardiographic 2- and 4-chamber views by means of the shortening of 48 radiants and the changes of 5 pre-defined areas. We used an extracardiac fixed axis reference system and an intracardiac floating reference system. We also calculated in 68 of the patients the interobserver variability of the data in each evaluation method. We demonstrated that the range of normal contraction and the reproducibility in the area-change method with a floating axis system was smaller compared to the radial shortening method. The interobserver variability in the 4-chamber view was better than in the 2-chamber view. Using the intracardiac fixed reference system in both methods, deviation from normal and interobserver variability was not acceptable for the detection of left ventricular wall motion abnormalities in both apical views. In general, we could also demonstrate that the interobserver variability was better and the range of deviation was smaller in the apical 4-chamber view than in the 2-chamber view. The practicability and quality of the apical projections were superior to the parasternal projections in the long and short axis. We conclude from our studies that left ventricular wall motion abnormalities in the echocardiographic 2- and 4-chamber views could best be demonstrated by using an area-change method with an intracardiac floating reference system.