Introduction
Multiple atrial tachycardias (ATs) in a patient related to spontaneous
polytropic atrial scars or radical atrial fibrillation (AF) ablation are
usually characterized by multiple mechanisms and require complex
ablation procedures.1 Scar-related electrically silent
areas (ESAs) and slow conduction to the isthmus are considered two of
the main mechanisms of these ATs. Despite targeted ablation of these
mechanisms and the use of high-resolution mapping, which provides
superior accuracy and understanding of the conduction features, these
ATs are associated with high recurrence.1,2 ATs in
these patients may be associated with more complex substrates and other
potential mechanisms. The phenomenon of a functional block has been used
to explain some complex sustained arrhythmias.3 ATs
sustained by a functional block line have been seldom
reported.4 In the present study, we assessed the
characteristics of the electrophysiological mechanism in a series of 8
patients with multiple ATs, and we present the role of the functional
block region in this specific category of AT.