18^th Annual Cardiologists Conference

Biography

Biography: Guy Hugues Fontaine

Abstract

Torsades de Pointes (TdP) is a rare but important cause of sudden death of young people with the genetically determined long or short QT syndrome. The length of the QT interval is directly related to the risk stratification of these patients modulated by genetic factors. TdP is also a major concern of the pharmaceutical industry for the development of any cardiac and even non-cardiac drugs. Endocardial recordings during TdP in human have brought new concepts for the understanding of this arrhythmia mechanism. Here, presence of intramyocardial conduction defects is demonstrated by the analysis of endocardial potentials observed on the QRS complexes in complete AV block. We present for the first time that patients (old females) with spontaneous complete AV block have a trouble in conduction not only on the AV conduction system but also inside the myocardium. This concept is reinforced by the absence of EGM but only far field potentials observed several times presented in a unique case. These images document the concept of depressed myocardium in which not only AV conduction but also intramyocardial conduction is impaired. It may explain that most TdP are transient and return spontaneously to sinus rhythm. Other data have demonstrated the presence of Wenckebach type I and Mobitz type2 in the myocardium of those patients suggesting that the myocardium has preferential pathways working as conduits transmitting ventricular activation. This is also in agreement with the identification of a specific genetic background.