Paroxysmal short runs of irregular narrow QRS tachycardia: What is the mechanism?

The present case that showed the frequent transition between left atrial tachycardia and AV nodal re-entrant tachycardia has never been reported. This instructive case highlights the need for careful interpretation of intracardiac electrocardiogram and suggests that differential pacing maneuvers are not feasible in transitional tachycardia with atrial fusion.

Fibrillatory wave amplitude on transesophageal ECG as a marker of left atrial low-voltage areas in patients with persistent atrial fibrillation.

Background: Low-voltage areas (LVAs) are frequently observed in patients with persistent atrial fibrillation (PeAF) and may represent adverse atrial remodeling. However, noninvasive method of evaluating LAVs is not well established.

Methods: In a cohort of 68 patients with PeAF, endocardial voltage maps of left atrium (LA) were created during sinus rhythm after pulmonary vein isolation (PVI).