Assessing myocardial viability in patients with myocardial infarction by quantitative tissue velocity imaging during low-dose dobutamine stress

Objective To assess myocardial viability in patients with myocardial infarction by quantitative tissue velocity imaging(QTVI) during low-dose dobutamine stress echocardiography(LDDSE). Methods Twenty patients with myocardial infarction underwent percutaneous transluminal coronary angioplasty(PTCA) or PTCA plus stent. LDDSE was performed before operation. QTVI was used to acquire the velocity and displacement curves of impaired myocardium before and during LDDSE and after operation. The strain(S) and strain rate(SR) of impaired myocardium were measured. Results In the group that myocardium was survived, both low-dose dobutamine stress and PTCA could significantly raise the SR and S of the impaired myocardium. At the end of low-dose (10 μg·kg -1·min -1) dobutamine stress, the magnitudes of SR and S were significant higher than that at rest[SR:( 1.0± 0.4)s -1 vs ( 0.2± 0.2)s -1, P 0.01;S: 0.10± 0.05 vs 0.03± 0.01, P 0.01]. There was no significant difference between the magnitudes of SR and S at the end of low-dose dobutamine stress and those after PTCA[SR:( 1.0± 0.4)s -1 vs ( 0.8± 0.2)s -1, P 0.05;S: 0.10± 0.05 vs 0.10± 0.04, P 0.05]. But in the group that myocardium was not survived, neither the low-dose dobutamine stress nor PTCA can significantly raise the SR and S of the myocardium. Conclusions QTVI can assess myocardial viability during LDDSE.