Effect of transducer placement on echocardiographic measurement of left ventricular dimensions.

An echocardiogram from the left ventricle may be used to estimate left ventricular volume and rate of circumferential fiber shortening, to measure posterior wall and interventricular septal thickness and to evaluate the normality of septal motion. Extended application of this technique in this laboratory has emphasized the need for a more standardized means of transducer location and direction. The effect of placing the ultrasonic transducer in several intercostal spaces along the left sternal border was tested in 14 patients. Variability in the left ventricular dimension and the difference in this dimension from end-diastole to end-systole were greater than for duplicate measurements from the same interspace. A system has been developed for more consistent placement of the transducer in each patient, using intracardiac landmarks and observation of transducer orientation to record specific cardiac structures.