Aims To evaluate whether plasma endothelin-1 (ET-1) is extracted or produced through the heart in patients with acute myocardial infarction (AMI), and the relationship between transcardiac extraction of plasma ET-1 and left ventricular (LV) remodelling. Methods and results We measured the plasma level of ET-1 in the aortic root (Ao) and coronary sinus (CS) in 48 consecutive patients, who received successful revascularization and enalapril, for a first anterior AMI. In the acute phase the plasma ET-1 level was significantly higher both in the Ao and the CS compared to the control subjects. However, the plasma ET-1 level was significantly lower in the CS than in the Ao in the acute phase and after 1 month. There were significant correlations between transcardiac extraction of ET-1 in the acute phase and LV ejection fraction and LV end-diastolic volume index (LVEDVI) after 1 month. Stepwise multivariate analysis showed that maximal creatine phosphokinase and transcardiac extraction of plasma ET-1 during the acute phase were independently and positively correlated with the absolute change in LVEDVI after 1 month. Conclusions These results indicate that elevated circulating ET-1 is extracted through the heart in patients with a first anterior AMI and that the extracted ET-1 plays a significant role in modulating post-infarct LV remodelling.