Aims: To determine the frequency and predictors of left ventricular dilatation assessed by magnetic resonance imaging among patients with a first acute myocardial infarction treated with successful primary angioplasty and stent.
Methods and results: Cine magnetic resonance imaging and late enhancement imaging were prospectively performed in 42 patients 1 month and more than 1 year after successful early reperfusion of a first acute ST elevation myocardial infarction (age 61 +/- 13 years, 76% men, 55% anterior myocardial infarction, and mean symptom-to-balloon time 199 +/- 130 min). Both at the 1-month and at the 15-month magnetic resonance imaging examinations, 57% of patients had left ventricular dilatation (end-systolic volume indexed > 36 ml/m2, values above the upper 95th percentile based on magnetic resonance imaging reference values for left ventricular size in normal participants). The most accurate predictor of left ventricular dilatation was maximum persisting single lead ST elevation 60 min after reperfusion (area under the curve 0.81, P = 0.001). Maximum single lead ST elevation was significantly and independently associated with larger end-systolic volume indexed (beta = 0.35, P = 0.040) after adjusting for muscle and brain isoenzyme of creatine kinase and echocardiographic wall motion score index.
Conclusion: More than half of patients with a first acute myocardial infarction have left ventricular dilatation despite successful primary coronary angioplasty. Maximum persisting single lead ST elevation 60 min after mechanical reperfusion represents a simple tool for predicting left ventricular dilatation.