The first European surgical intervention of a Wolff-Parkinson-White syndrome guided by epicardial mapping was performed by C. Cabrol and G. Guiraudon in May 1971 in Paris, in a patient with a type AB syndrome. Experiments had been performed in animal models for six months before its application to the humans, in order to develop the equipment (amplifiers, electrodes and protocols). In December 1971, the same methodology was used to manage one case of post-myocardial infarction ventricular tachycardia. An incision in the diaphragmatic wall of the left ventricle (where the "site of origin" was determined) proved successful. In one patient with VT studied in December 1972, the first detailed sinus rhythm epicardial mapping was performed in 85 test points to describe completely the epicardial activation. This case presented with a left bundle branch block and superimposed trouble of parietal conduction because of an important anteroseptal aneurysm. In May 1973, in a patient with idiopathic dilated cardiomyopathy two transmural incisions at the "site of origin" of ventricular tachycardias proved effective in preventing recurrence of ventricular arrhythmias of two different morphologies. Epicardial delayed potentials were clearly documented. In October 1973 in the 1st case of Arrhythmogenic Right Ventricular Dysplasia, a simple incision made at the site of origin of ventricular tachycardia proved successful to prevent recurrence of the arrhythmia and contributed to the identification of this disease. The endocavitary catheter ablation (fulguration) was discovered in our laboratory in 1979. It was used intentionally for the first time in 1986 in a patient with Wolff-Parkinson-White syndrome with multiple mechanisms of reciprocating tachycardia. His bundle ablation proved clinically effective confirming that it was the elective critical pathway for tachycardia perpetuation. Localization of the site of slow conduction in ventricular tachycardia was important to delineate precisely the VT critical pathway in order to guide radiofrequency and fulguration techniques.