OBJECTIVE To demonstrate postinfarction myocardial oedema in humans with particular reference to the longitudinal course, using magnetic resonance imaging (MRI).

DESIGN Prospective observational study. Subjects were studied one week, one month, three months, six months, and one year after presenting with a myocardial infarct.

SETTING Cardiology and magnetic resonance departments in a Danish university hospital.

PATIENTS 10 patients (three women, seven men), mean (SEM) age 58.2 (3.20) years, with a first transmural myocardial infarct.

MAIN OUTCOME MEASURES Location and duration of postinfarction myocardial oedema.

RESULTS All patients had signs of postinfarction myocardial oedema. The magnetic resonance images were evaluated by two blinded procedures, employing two MRI and two ECG observers: (1) MRI determined oedema location was compared with the ECG determined site of infarction and almost complete agreement was found; (2) the time course of postinfarction myocardial oedema was explored semiquantitatively, using an image ranking procedure. Myocardial oedema was greatest at the initial examination one week after the infarction, with a gradual decline during the following months (Spearman's rank correlation analysis: ρ_{observer 1} = 0.94 (p < 0.0001) and ρ_{observer 2} = 0.97 (p < 0.0001)). The median duration of oedema was six months.

CONCLUSIONS Postinfarction myocardial oedema seems surprisingly long lasting. This observation is of potential clinical interest because the oedema may have prognostic significance.