This symposium is the fourth of a series of scientific meetings in the field of echocardiology, held at the Erasmus University, Rotterdam.* The series was initiated by Klaas Born, who organized the first two meetings, and was continued by Charles Lancee. These previous symposia met with great success. These proceedings comprise most of the invited lectures and free commu nications which had their' live performance' during the 4th Symposium on Echocardiology. We decided, again, to maintain one ofthe most striking features of the last meetings: having the proceedings available at the time of the meeting. As a consequence, the authors-to-be were confronted with a very tight schedule. The editing time was also limited and therefore neither terminology nor units have been completely standardized. However, as a result, these proceedings do reflect the 'state of the art' in echocardiology. This is not a textbook on echocardiology, but cardiologists and techni cians, with experience in the field of echocardiology, will certainly appreciate the educational features of this book. This symposium was organized in association with Interuniversity Institute of Cardiology, Amsterdam, the Netherlands. Dutch Society of Ultrasound in Medicine and Biology Dutch Heart Foundation, The Hague, the Netherlands European Society of Cardiology Financial support was given by Interuniversity Institute of Cardiology, Amsterdam, the Netherlands University-fund Rotterdam Foundation, Rotterdam, the Netherlands Dutch Heart Foundation, The Hague, the Netherlands.