Objective: To evaluate the relationship between myocardial systolic, diastolic functions and perfusion in coronary artery stenosis using velocity vector imaging (VVI) and myocardial contrast echocardiography (MCE).
Methods: Stenoses in the anterior descending branch of the coronary artery were induced in 8 dogs. Before and after coronary artery stenosis, two-dimensional images of the left ventricular mastoid muscle section on the short axis at rest and in the peak dose of dobutamine were obtained for evaluation of VVI and MCE. The myocardial blood flow A.beta values, peak systolic strain rate (SRsys) and peak diastolic strain rate (SRdia) in the direction of the circumference of the short axis were measured.
Results: At rest, only severe coronary stenosis resulted in significantly lowered SRsys, SRdia and A.beta value of the stenotic bed compared to the values before the stenosis (-1.1-/+0.50 vs -1.62-/+0.50, 1.19-/+0.48 vs 1.75-/+0.51, 0.4-/+0.21 vs 0.80-/+0.47, P<0.05). In stress, SRsys, SRdia and A.beta value of the stenotic bed gradually decreased as coronary stenosis worsened (-4.31-/+1.14 vs -3.20-/+0.98 vs -1.18-/+0.64, 4.51-/+1.13 vs 3.39-/+0.98 vs 1.37-/+0.64. 3.54-/+1.95 vs 1.81-/+0.89 vs 0.82-/+0.42, P<0.05). Both at rest and in stress, good correlations were noted between SRsys and SRdia (r(rest)=0.88, r(stress)=0.96, P<0.01), between SRsys and the standard A.beta values (r(rest)0.56, r(stress)=0.71, P<0.01), and between SRdia and A.beta (r(rest)=0.57, r(stress)=0.72, P<0.01) in the direction of the circumference of the short axis.
Conclusions: Using VVI and MCE, the changes in myocardial perfusion and the systolic and diastolic functions in the direction of the circumference can be observed dynamically. VVI may help assess the condition of myocardial perfusion by evaluating the systolic and diastolic function.