Electrophysiological Mechanism of the Characteristic Electrocardiographic Morphology of Torsade de Pointes Tachyarrhythmias in the Long-QT Syndrome Detailed Analysis of Ventricular Tridimensional Activation Patterns

摘要: Background The long-QT syndrome (LQTS) is an electrophysiological (EP) entity characterized by prolongation of cardiac repolarization and the occurrence polymorphic ventricular tachyarrhythmias (VTs), sometimes with a twisting QRS morphology, better known as torsade de pointes (TdP). In present study, detailed analysis tridimensional activation patterns during nonsustained TdP VT was performed to provide EP mechanism periodic transition in axis. Methods Results studies were conducted anthopleurin-A canine model LQTS. Tridimensional isochronal maps constructed from 256 bipolar electrograms obtained use 64 plunge needle electrodes. 26 episodes VT, could be accurately QRS-axis transitions surface ECGs. initial beat all VTs consistently arose subendocardial focal activity, whereas subsequent beats due reentrant excitation i...