All patients should give their written informed consent before entry into the study. Patients with clinical or laboratory evidence of an acute coronary syndrome as well as patients with major arrhythmias will be excluded if these conditions are likely to be the main cause of the symptoms. In contrast, patients with aspecific electrocardiographic ST segment changes and/or with a slight elevation of plasma troponin levels may be included as these conditions are known to be frequently associated with AHFS and it is generally not possible to establish to which extent they are the cause rather than the consequence of the hemodynamic decompensation. The patients in whom a coronary revascularization procedure (either PTCA or CABG) is planned in the next 3 months and the patients with non cardiac concomitant diseases that may influence outcome as primary factor will be excluded from the study.