Background .– Myocardial viability can be assess by several imaging methods including low dose dobutamine stress echocardiography (DSE) and contrast-enhanced magnetic resonance imaging (Ce-MRI). DbE is a widely available and low cost approach but its assessment remains subjective and relies on semiquantitative evaluation of endocardial excursion and wall thickening, requiring adequate training.

Recent software provides fast and accurate quantification of myocardial strain using 2D speckle tracking. Thus, we sought to compare the results of 2D global and segmental strain both at rest and during low dose DSE to Ce-MRI for the assessment of myocardial viability after acute Myocardial infarction (MI).

Patients and results .– Between 2011 December and April 2012, we included 12 consecutive patients aged 52 ± 12 (92% men) who had a coronary angioplasty in the acute phase of MI. One month after MI, all patients had DSE and Ce-MRI on the same day. Left ventricular ejection fraction (EF) at rest assessed in MRI correlated to both biplane echocardiographic EF (48 ± 12% vs. 50 ± 12%, r = 0.9, P = 0.001) and global longitudinal strain (GLS) (−15 ± 5%, r = 0.68, P = 0.016). A 17 segments model was used. Two hundred and four left ventricular segments were studied in both MRI, conventionnal echocardiography and 2D strain, and were divided in three groups according to the result of Ce-MRI: 131 (64%) segments were considered normal, 25 segments (12%) had non-transmural enhancement (NTM) and 48 segments (24%) had transmural enhancement (TM). Peak longitudinal strain (LS) at rest was significantly reduced in NTM and TM segments compared to normal segments (−10 ± 7% vs. −18 ± 5%, P = 0.0001). However, LS at rest was not statistically different between NTM and TM segments (−12 ± 6% vs. −9 ± 7%, P = 0.19). GLS during low dose DSE tended to be higher in NTM segments than in TM segments (−16 ± 7% vs. −12 ± 8%, P = 0.05). At rest, a normal LS ≤ −18% in a segment allowed to predict the absence of NTM or TM scar with a sensibility of 49%, a specificity of 84%, a predictive positive value of 84% and a predictive negative value of 47%.

Conclusion .– Conventional DSE provides a reliable assessment of myocardial viability after acute MI compared to Ce-MRI. Isolated longitudinal myocardial deformation analysis may improve segmental analysis but failed to discriminate TM from NTM extent of MI. Radial or circumferential strain analyses may be mandatory to improve the performance of DSE to predict viability.