Evaluation of Regional Left Ventricular Function by Three-dimensional Echocardiography

Background. Three-dimensional (3D) echocardiography (3DE) has demonstrated superior accuracy and reproducibility over conventional 2DE for measuring left ventricular (LV) volumes. This study evaluates the clinical feasibility of 3DE for assessing regional LV function by measuring segmental volumes and segmental ejection fraction (EF). Methods. Freehand 3DE was performed in 9 subjects using an electromagnetic tracking device. The image acquisition was obtained by manually rotating the probe into the apical position. After automated border detection and computation were performed, a reconstructed 4D (3D + time) image of LV with 16 divided LV segments was obtained. Global and segmental volume changes with time were plotted as a time-volume curve. Reference values of segmental wall motion parameter and segmental EF were calculated from 6 healthy subjects and were used for comparison with corresponding values of patients with wall-motion abnormalities. Z scores (the units of SD from the normal reference) converted from the segmental EF were also used for comparison. Results. In normal subjects, segmental end-diastolic volume (EDV) ranged from 2.2 to 8.8 mL (5.1±1.8 mL), and segmental end-systolic volume (ESV) ranged from 0.4 to 4.6 mL (1.7±0.8 mL); segmental stroke volume (SV) ranged from 1.4 to 7.1 mL (3.4±1.3 mL), and segmental EF ranged from 46 to 88 % (67±11 %). In a patient with anterior myocardial infarction (MI), the segmental EDV and ESV of the anterior wall are much larger than other segments (anterior basal segment: 17.7 and 17.5 mL, mid-segment: 16.6 and 15.6 mL, respectively). In a patient with inferior MI, segmental SV was <1.0 mL and EF was <40 % in the inferior and inferoseptal segments. In a patient with dilated cardiomyopathy, the segmental EF ranged from 13 to 34% (20.6±5.9%) and all Z scores were <-2. Conclusions. The present study introduces new parameters of regional LV function that might help to evaluate patients with LV wall motion abnormalities.