REGIONAL MEAN SYSTOLIC MYOCARDIAL VELOCITY ESTIMATION BY REAL-TIME COLOR DOPPLER MYOCARDIAL IMAGING - A NEW TECHNIQUE FOR QUANTIFYING REGIONAL SYSTOLIC FUNCTION

A new color Doppler myocardial imaging (CDMI) system with high spatial and temporal resolution and novel postprocessing modalities has been developed that could allow quantifiable stress echocardiography. The p urpose of this study was to determine whether regional myocardial syst olic velocities could be accurately and reproducibly measured both at rest and during bicycle ergometry by using CDMI. Thirty normal subject s were examined with CDMI at rest, and peak mean systolic myocardial v elocities (MSV) were measured for 34 predetermined left ventricular my ocardial segments. Interobserver variability and intraobserver variabi lity were established for all segments. Submaximal bicycle ergometry w as performed in 20 normal subjects by using standardized weight-relate d increases in workload. MSV were measured at each step of exercise fo r 16 left ventricular stress echo segments. At rest, a base-apex gradi ent in regional MSV was recorded with highest longitudinal short-ening velocities at the base. A similar pattern was noted for circumferenti al shortening MSV. Measurements were predictable and highly reproducib le with low interobserver and intraobserver variability for 26 of 34 s egments. Reproducibility was poor for basal anteroseptal segments in a ll views and mid anterior, anteroseptal, and septal segments in the sh ort-axis views. During exercise, mid and basal segments of all walls s howed a significant increase of MSV between each workload step and for apical segments between alternate steps. The resting base-apex veloci ty gradient observed at rest remained in all walls throughout ergometr y. Thus a CDMI system with improved spatial and temporal resolution an d postprocessing analysis modalities provided reproducible and accurat e quantification of segmental left ventricular circumferential and lon gitudinal contraction both at rest and during exercise.