This book contains the manuscripts of the majority of the papers given during the symposium 'Improvement of Myocardial Perfusion' which was held from Sep­ tember 27-29,1984 in Mainz/Germany. It has been the purpose of this meeting to focus the interest of scientifically and clinically interested cardiologists on the new developments in this field. We therefore chose the subtitle 'Medical-Mechanical -Surgical Approach'. The medical improvements in myocardial perfusion have been brought about by the application of streptokinase, urokinase and tissue-type plasminogen ac­ tivator in the first hours after the onset of an acute myocardial infarction. The different modes of application and the possibilities to evaluate and eventually to quantify the results of these treatments were addressed during the first part of the meeting. The mechanical way to improve perfusion nowadays mainly consists of the application of intracoronary balloon angioplasty. Although since 1977 the treat­ ment has become a routine method, several questions are still open such as the exact mode of action, the reaction of the vessel wall, the optimal pressure and balloon size as well as the long term results and the prevention of restenosis.