The first invasive evaluation of cardiac arrhythmias in humans was performed in 1967 in Paris (Prof. P. Coumel) and Amsterdam (Prof. D. Durrer). This was the start of a rapid increase in our knowledge of the diagnosis, mechanism and treatment of cardiac arrhythmias. In that same year Prof. Hein J.J. Wellens became cardiologist in the Wilhelmina Gasthuis in Amsterdam. Initially in Amsterdam (1967-1977) and later on in Maastricht (from 1977), he was the driving force for many breakthroughs in clinical cardiac electrophysiology. With an active interplay between the knowledge derived from the...