Assessment of temporal heterogeneity and regional motion to identify wall motion abnormalities using treadmill exercise stress three-dimensional echocardiography

Background Exercise 3-dimensional echocardiography (3DE) may avoid the problem of poorly matched pre- and post-exercise 2-dimensional echocardiograms (2DE), and contraction front mapping (CFM) may be used to quantify the temporal homogeneity of contraction. We compared 3DE with 2DE for identification of angiographically significant disease.
Methods Conventional 2DE and 3DE at rest and peak stress were performed in 110 patients (78 men, aged 60 ± 11 years) who underwent angiography within 6 months. Offline assessment of CFM was performed qualitatively (delayed regional relaxation in a coronary territory) and quantitatively (difference in regional and global contraction delays from rest to peak in individual segments). The accuracy of each test was calculated for identification of 70% or more diameter angiographic stenoses.
Results Patients were excluded for nondiagnostic stress (n = 12) or poor-quality 3DE (n = 8). Time until end of 2DE acquisition was 58 ± 25 seconds, and time until end of 3DE (taken after 2DE) was 109 ± 55 seconds. Receiver operating characteristic analyses were used to define normal cutoff ranges of contraction delays for the following coronary territories: left anterior descending (≤10%), left coronary artery (≤10%), right coronary artery (≤11%), and overall (≤10%). The concordance between angiography and qualitative CFM (63%) was similar to quantitative CFM (70%). The sensitivity of wall motion assessment at 3DE (40%) was lower than CFM (55%, P = .04) and 2DE (83%, P < .01) at comparable levels of specificity (65%, 84%, and 78%).
Conclusion Although the higher specificity of 3DE may represent avoidance of false-positives from off-axis imaging, the sensitivity of 3DE is insufficient for clinical use. Analysis of the temporal distribution of contraction may be more sensitive than 3D wall motion assessment for identification of ischemia at exercise 3DE.