Comparison of left ventricular stroke volume determination by real-time three-dimensional echocardiography and conventional two-dimensional echocardiography: An animal study during non-ischemic and ischemic conditions

Recently, 3D echocardiography (3DE) has developed the capability to capture 3D images in real-time and has been reported to be accurate for estimating left ventricular (LV) volume. We hypothesized that real-time 3DE could determine LV stroke volumes (SV) more accurately than conventional 2DE. Purpose: The aim of this study was to compare 2DE and 3DE for estimating LV stroke volumes during a variety of hemodynamic conditions, including left anterior descending (LAD) coronary artery occlusions. Methods: During a total of 30 hemodynamic conditions in 6 sheep with chronic aortic regurgitation, electromagnetic (EM) flow probes and meters were used to obtain LV SV. LV end-diastolic (LV EDV) and LV end-systolic volumes (LV ESV) were measured using real-time 3DE with Simpson's rule (slice spacing 7 mm). Results: For 24 conditions without LAD occlusions, SV by EM ranged from 27 to 66 ml (average 45±10ml). The correlation for LV SV measured by 3DE and that by EM was excellent (r = 0.92, y = 0.91x + 3.6, Δ = -1±4 ml, n = 24), and better than that between 2DE and EM (r = 0.62, y= 0.68x + 8.8, Δ= -5.6 ± 9.4 ml, p = 0.0003). For 6 conditions during LAD occlusion, SV by EM ranged from 26 to 58 ml (average 41 ± 12ml). SV derived from 3DE also agreed well with values derived by EM (r = 0.96); however, the r-value between 2DE and EM was reduced to 0.58. Conclusion: Real-time 3DE provided accurate assessment of LV SV under both ischemic and nonischemic conditions, while conventional 2DE showed poor correlations with reference standards, especially for SVs during coronary artery occlusion.