Myocardial contrast echocardiography accurately reflects transmurality of myocardial necrosis and predicts contractile reserve after acute myocardial infarction.
BACKGROUND
Both myocardial contrast echocardiography (MCE) and cardiovascular magnetic resonance (CMR) can identify myocardial necrosis after acute myocardial infarction (AMI). However, transmural extent of infarction (TEI) correlates of myocardial perfusion by MCE after AMI are unknown. We sought to ascertain the ability of MCE to (1) predict TEI as defined by contrast-enhanced CMR and (2) to compare the relative accuracy of these techniques to predict contractile reserve late after AMI.


METHODS
MCE and CMR were performed in 42 patients with AMI 7 to 10 days after thrombolysis. Contractile reserve with low-dose dobutamine was evaluated 12 weeks after revascularization.


RESULTS
Both qualitative (myocardial contrast intensity) and quantitative MCE [peak contrast intensity, microbubble velocity (beta), and myocardial blood flow] showed a significant (P < .0001) inverse relationship with increasing TEI. However, beta was the single best predictor of TEI (P = .002). Both qualitative MCE and CMR predicted contractile reserve similarly (area under receiver operating characteristic curve were 0.84 and 0.80, respectively). Qualitative and quantitative MCE parameters as well as CMR correlated significantly with the degree of contractile reserve (P < .001). Multiple logistic regression analysis using clinical, electrocardiographic, MCE, and CMR parameters showed that both MCE (OR = 0.03, 95% CI 0.01-0.10, P < .001) and CMR (OR = 0.11, 95% CI 0.04-0.26, P < .001) are independent predictors of contractile reserve. The most discriminative quantitative parameters for prediction of contractile reserve were microbubble velocity (P < .001) and myocardial blood flow (P = .001) assessed by MCE.


CONCLUSIONS
MCE reflects the transmural extent of AMI as assessed by CMR. Both techniques predict contractile reserve.
Janardhanan
Rajesh
R
Department of Cardiology, Northwick Park Hospital, Harrow, UK.
Moon
James C C
JC
Pennell
Dudley J
DJ
Senior
Roxy
R
D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis / Q000175:diagnosis / Q000000981:diagnostic imaging; D015588:Observer Variation; D010743:Phospholipids; D013459:Sulfur Hexafluoride; D015912:Thrombolytic Therapy
D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride