Early contrast-enhanced MRI predicts late functional recovery after reperfused myocardial infarction

Background-We have observed 3 abnormal patterns on contrast-enhanced MRI ea rly after reperfused myocardial infarction (MI): (1) absence of normal firs t-pass signal enhancement (HYPO), (2) normal first pass signal followed by hyperenhanced signal on delayed images (HYPER), or (3) both absence of norm al first-pass enhancement and delayed hyperenhancement (COMB). This study e xamines the association between these pattern in the first week after MI an d late recovery of myocardial contractile function by use of magnetic reson ance myocardial tissue tagging. Methods and Results-Seventeen patients (14 men) with a mean age of 53 +/- 1 2 years were studied after a reperfused first MI. Contrast-enhanced images were acquired immediately after bolus administration of gadolinium and 7+/- 2 minutes later. Tagged images were acquired at weeks 1 and 7. Circumferent ial segment shortening (%S) was measured in regions displaying HYPER, COMB, or HYPO contrast patterns and in remote regions (REMOTE) at weeks 1 and 7. at week 1, %S was depressed in HYPER, COMB, and HYPO (9+/-8%, 7+/-6% and 5 +/-4% respectively) and were less than REMOTE ( 18+/-6%. P<0.003). However, in HYPER, %S improved at week 7 from 9+/-8% to 18+/-5% (P<0.001 versus wee k 1), In contrast, HYPO did not improve significantly (5+/-4% to 6+/-3%, P= NS) and COMB tended to improve 7+/-6% to 11+/-6% (P=0.06). Conclusions-HYPER has partially reversible dysfunction and represents predo minantly viable myocardium. COMB shows borderline improvement and likely co ntains an admixture of viable and necrotic myocardium. HYPO shows little fu nctional improvement at 7 weeks. presumably because of irreversible myocard ial damage.