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

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; X-2 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.