Early Assessment of Left Ventricular Viability of Dyskinesia and Akinesia Myocardium in Patients with Acute Myocardial Infarction: Real-time Contrast Echocardiography Versus Low-dose Dobutamine Echocardiography

Purpose: Low-dose dobutamine echocardiography (LDDE) has been demonstrated as an accurate imaging modality to identify viability after acute myocardial infarction (AMI), but LDDE has its limitations. Myocardial contrast echocardiography (MCE) is a good tool to assess microvascular perfusion. This study was undertaken to compare the effect of real-time MCE and LDDE in early assessment of left ventricular (LV) viability of dyskinesia and akinesia myocardium in patients with AMI. Methods: Forty-five patients had 2-dimensional echocardiography, MCE and LDDE within 1 week after AMI attack. Two-dimensional echocardiography for evaluation of LV viability was performed within 4 months after discharge. Results: Totally 260 segments of dyskinesis or akinesis were analyzed. MCE visualized perfusion segments, either homogenous or patchy contrast opacification and had a sensitivity of 81.4%, specificity of 76.7%, accuracy of 79.4%, positive predictive value of 82.8% and negative predictive value of 75.0% in predicting LV viability. The accuracy was comparable with LDDE (79.4% vs. 76.8%, p = 0.52), although MCE had higher sensitivity (81.4% vs. 68.9%, p < 0.005) and LDDE had higher specificity (76.7% vs. 87.6%, p < 0.01). Average time for MCE study was lower than that of LDDE (374 102 seconds vs. 785 216 seconds, p < 0.001). MCE studies were performed and completed without any complication when compare to 6.7% complication rate in the LDDE studies (p < 0.001). Conclusions: Real-time MCE is more time-saving and safer than LDDE. MCE also has comparable accuracy with LDDE for early assessing of LV viability in patients with AMI, despite the limitation of attenuation artifacts in the infero-posterior segments.