Cardiac Mapping in Variants of the Ventricular Preexcitation Syndrome

Abstract

In this chapter we describe the identification, the structural-functional relation and the management of relatively rare intracardiac conduction pathways leading to variants of ventricular preexcitation. Their proper recognition is a must for the arrhythmologist involved in the ablative intracardiac treatment of these patients. Successively are discussed: atriofascicular pathways, short decrementally conducting accessory pathways, fasciculoventricular pathways, nodoventricular and nodofascicular pathways. Detailed information is given on how to use the appropriate electrophysiological maneuvers necessary to identify each of these variants, how to map them, and how to choose the best strategy for ablation, and how to document the success of that intervention. Special attention is given to the correct diagnosis of the fasciculoventricular pathways, when to be suspicious of the presence of a PRKAG2 mutation and how to correctly differentiate those from septal atrioventricular node (AV) pathways. Important knowledge to avoid the mistake of trying to ablate them with the potential of causing iatrogenic AV block, because they are not involved in tachycardia circuits.