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Value of low dose dobutamine Doppler tissue imaging for detecting hibernating myocardium
1Department of Cardiology, Tongji Hospital, Tongji Medical University, Wuhan 430030.
Insights
Doppler tissue imaging (DTI) effectively differentiates hibernating myocardium from necrotic tissue in patients with coronary artery disease. DTI reveals distinct responses to dobutamine stress, aiding in viability assessment.
Area of Science:
- Cardiology
- Medical Imaging
- Echocardiography
Background:
- Coronary artery disease often leads to chronic left ventricular dysfunction.
- Assessing myocardial viability is crucial for treatment decisions in such patients.
Purpose of the Study:
- To evaluate the utility of Doppler tissue imaging (DTI) in detecting viable hibernating myocardium.
- To compare DTI's performance with standard echocardiography during low-dose dobutamine stress.
Main Methods:
- 20 patients with coronary artery disease and left ventricular dysfunction underwent low-dose dobutamine stress echocardiography and DTI.
- Asynergic myocardial segments were analyzed for changes in function and DTI parameters (Vs, VR) post-dobutamine.
Main Results:
- Dobutamine infusion improved function in 35% of asynergic segments (hibernating myocardium).
- Post-dobutamine, velocity of S wave (Vs) and velocity reserve (VR) were significantly higher in the hibernating group compared to the non-viable group.
- Segments with VR ≤ 0 showed no viability (95.7%), while segments with VR > 80% indicated viability (86%).
Conclusions:
- Doppler tissue imaging can differentiate hibernating from necrotic myocardium based on their response to dobutamine stress.
- Specific velocity reserve (VR) thresholds (≤ 0% and > 80%) are clinically significant for assessing myocardial viability.
Abstract:
In order to assess the value of Doppler tissue imaging (DTI) in detecting viable hibernating myocardium, 20 patients with coronary artery disease and chronic left ventricular dysfunction underwent low dose dobutamine stress echocardiography and low dose dobutamine stress DTI. The results showed that among the 100 asynergic segments, 35 segments showed improvement after dobutamine infusion (group H) and no changes were observed in the remaining 65 segments (group N). The left ventricular echocardiographic score index decreased from 1.60 +/- 0.35 to 1.44 +/- 0.36 (n = 20, P < 0.01). During low dose dobutamine stress DTI, there was no difference in the values of velocity of S wave (V.) before dobutamine infusion between two groups. However, after dobutamine infusion, the values of Vs and VR in group H were significantly higher than those in group N (Vs: 10.1 +/- 3.0 cm/s vs 7.3 +/- 2.2 cm/s, P < 0.01; VR: 60% +/- 41% vs 25% +/- 32%, P < 0.001), 95.7% asynergic myocardial segments with VR < or = 0 had no viability while 86% asynergic segments with VR > 80% were viable myocardium. It is concluded that the different reactions to dobutamine stress between hibernating and necrosis myocardium could be showed by DTI and it is more clinically significant when VR < or = 0 and VR > 80%.