Background: The relation between preceding angina pectoris (PAP), rheologic blood properties as indicated by plasma fibrinogen levels (FiB) and left ventricular (LV) function after myocardial infarction (MI) remain uncertain.Methods: 92 patients (pts) with proven anterior MI were investigated. No interventional or thrombolytic therapy was performed. Inclusion criteria were: 1. Isolated proximal occlusion of the left anterior descending artery (LAD) >3 weeks after MI. 2. Remaining coronary arteries and corresponding LV wall segments were normal. Pts. were divided into 4 groups (gr.): Results: The 4 gr. were comparable regarding age, gender, age of MI and risk factors. Pts. in gr. 3 and 4 received more frequent ACE inhibitors than gr. 1 and 2 pts.. LV ejection fraction (EF) decreased and the number of akinetic segments (AS) increased from gr. 1 to 4: Conclusion: PAP has a protective effect on the LV-function after anterior MI despite permanent occlusion of the LAD, presumably by the development of coronary collaterals. This is attenuated by unfavourable rheologic blood properties as indicated by increased FiB concentrations. Pts. without PAP and elevated FiB levels are at highest risk for a large MI and reduced LV-function.