Short-Lasting Episodes of Torsade de Pointes in the Chronic Atrioventricular Block Dog Model Have a Focal Mechanism, While Longer-Lasting Episodes Are Maintained by Re-Entry

Abstract

TdP can be driven by focal activity as well as by re-entry depending on the duration of the episode. NT episodes are always maintained by re-entry, which can be identified in local unipolar electrograms by shorter interbeat intervals and smaller deflection amplitude.

Directed networks as a novel way to describe and analyze cardiac excitation: Directed Graph mapping

“…We chose a certain time t. Starting from this time, we find LAT 1 , ..LAT n which are the first LAT larger than t for each electrode in our system of n electrodes. We then draw arrows as follows (25). Suppose electrode 1 and 2 form a pair of neigh- bors.…”

“…However, in contrast with DG-mapping, this methodology precluded the possibility of detecting rotational activity, and does not represent the actual wave excitation. In a model of chronic atrial ventricular block, we used directed networks for the first time to determine the mechanism underlying Torsade de Pointes (25). However, again, we did not use it to fully describe the electrical excitation as in this work.…”

“…However, again, we did not use it to fully describe the electrical excitation as in this work. Therefore, to our knowledge, this is the first study where directed networks were used to describe electrical excitation, building on our previous work in the CAVB dog (25).…”

Sex hormones and jumping heart beats

“…Interestingly, dofetilide‐induced ectopic beats and TdP initiates at the region of highest spatial dispersion of repolarization . TdP always starts by a focal mechanism, whereas sustained TdP requires an additional reentry mechanism . From a study in chronic AV block dogs, using a late sodium current inhibitor, we concluded that (long term) arrhythmia perpetuation depends on spatial dispersion, rather than focal activity .…”

Fragmented endocardial signals and early afterdepolarizations during torsades de pointes tachycardia

“…The exact mechanism of torsades de pointes tachycardia (TdP) in high-degree AV block (AVB) and long QT syndrome (LQTS) has been puzzling electrophysiologists over the past decades [1][2][3][4][5]. This syndrome or its variants are a rare but important cause of sudden death in young people with a genetically determined form of LQTS [6,7].…”