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...