[Multiple myocardial infarctions: pancoronary destabilization evaluated by cardiac MRI]

Complete intravascular ultrasound study examination of all three coronary arteries in patients with first acute coronary syndrome very frequently revealed one or more atherosclerotic plaque ruptures associated with the culprit lesion. The aim of this study was to evaluate using cardiac MRI the incidence of multiple necroses in patients with myocardial infarction. The study sought to detect delayed enhancement in a zone different from the necrosis area concerned by the culprit occlusion.

Eighty consecutive patients who were referred for a first myocardial infarction underwent angioplasty within the first 12 hours after chest pain beginning. Each patient was examined within four to eight days following the acute phase. Cardiac MRI evaluated left-ventricle function (TrueFISP sequence) and used a T2 weighted short-inversion-time, inversion recovery sequence (STIR) in order to visualize myocardial oedema; delayed enhancement imaging data were then acquired after injection of gadolinium.

In eight patients (10%), we observed two delayed enhancement areas associated with wall-motion abnormalities. One was attributed to the culprit occlusion; the second corresponded to a different coronary artery. In five patients, this second zone was related to an old coronary occlusion confirmed by angiography and the STIR sequence. However, in three patients, the second delayed enhancement area corresponded to a coronary artery stenosis with normal flow.

In patient with acute myocardial infarction, MRI sometimes detects a necrosis area which was not initially suspected. This observation illustrates the consequences of pancoronary destabilization.