Quantitative segmental analysis of myocardial perfusion to differentiate stress cardiomyopathy from acute myocardial infarction: A myocardial contrast echocardiography study

BACKGROUND: Both stress cardiomyopathy (SCMP) and acute myocardial infarction (AMI) present with similar clinical symptoms and signs, and apical akinesis. HYPOTHESIS: Quantitative segmental analysis of myocardial contrast echocardiography (MCE) helps to differentiate AMI from SCMP. METHODS: Real-time MCE was performed in 33 consecutive patients who presented with an acute symptom/sign and a new apical akinesis on echocardiography. In 18 left ventricular (LV) myocardial segments, a replenishment curve was obtained in each segment to measure peak plateau myocardial contrast intensity (MCI) (A) and the replenishment curve slope (β). The calibrated MCI was also measured in each segment. RESULTS: Among 33 patients, 22 were diagnosed with SCMP and 11 were diagnosed with AMI according to comprehensive diagnostic criteria. A, β, Aβ, and the calibrated MCI were lower in akinetic than in normokinetic segments in both the SCMP and AMI groups. In the akinetic segments, A, β, Aβ, and the calibrated MCI in SCMP patients were each higher than those in AMI patients. In patient-based analyses, areas under the ROC curves of A, β, Aβ, and the calibrated MCI for diagnosing AMI were 0.769, 0.607, 0.822, and 0.934, respectively. The optimal cutoff values to diagnose AMI were Aβ < 3.7 dB/sec (sensitivity 82%, specificity 82%) and a calibrated MCI < -23 dB (sensitivity 91%, specificity 95%). CONCLUSIONS: Although myocardial perfusion is relatively reduced in the akinetic segments of SCMP, a quantitative segmental analysis of myocardial perfusion using MCE helps to discriminate AMI from SCMP.