Mark Josephson: Pioneer, Educator and Mentor to a Generation of Cardiac Electrophysiologists

In January 2017 we lost a giant in cardiac electrophysiology, whose work and teachings touched all of us working in the field. Mark Josephson’s early work, building on the work of Hein Wellens in using programmed stimulation and catheter mapping to understand scar-related ventricular tachycardias, led the way to surgical and then catheter ablation as a viable therapy for that arrhythmia. His seminal observations are many and catalogued in ‘The Josephson School’ a wonderful book with 59 Chapters and extensive commentary devoted to his research.1 In the area of scar-related VT alone his work characterising electrograms in infarct scars and defining their relation to reentry circuits led to the development of substrate mapping techniques in common use today. His attention to the details of recording techniques helped establish the standards for electrophysiology studies. His investigational studies are not limited to ventricular arrhythmias but extend across the spectrum of cardiac electrophysiology. He was a superb observer with a talent for recognising subtle, unexpected events and delving deep to explore their potential mechanisms and significance.