The Relationship between Transmural Extent of Infarction on Contrast Enhanced Magnetic Resonance Imaging and Recovery of Contractile Function in Patients with First Myocardial Infarction Treated with Thrombolysis

Abstract

Background: The aim of the current study was to assess the utility of transmurality of delayed enhancement on cardiac magnetic resonance imaging (MRI) in predicting functional recovery in patients with first ST-elevation myocardial infarction (MI) who had received thrombolysis. Methods: Nineteen patients underwent cine and contrast-enhanced MRI 3 days and 8 weeks after MI. The transmural extent of infarction (TEI) was determined from the late enhancement component of the first scan. Segmental wall thickening was scored from the cine components of both the initial and follow-up scans. Results: The TEI was inversely related to the likelihood of improvement in wall thickening; χ² test for trend = 53.9, p < 0.0001. Delayed enhancement with >50% transmurality predicted a lack of recovery with 82% sensitivity and 54% specificity. The equivalent values for >75% transmurality were 57 and 77%, respectively. The proportion of the left ventricular segments exhibiting functional recovery was related to the percentage of the left ventricle that was severely dysfunctional but had ≤50% TEI (r = 0.49, p = 0.03). In a backward conditional regression model this was the only independent predictor. Conclusion: These data suggest that TEI, determined by contrast-enhanced cardiac MRI, is a useful predictor of the likelihood, or otherwise, of functional recovery following acute MI treated with thrombolysis.