High-density mapping of de novo focal atrial tachycardias using a new software: Protected low-voltage areas by zones of conduction delay

Background: The pathophysiological mechanism of focal atrial tachycardias (AT) remains obscure.

Methods: Fifteen patients (6 males, age 45 ± 18) with focal AT underwent high-density activation mapping using a new software called extended early-meets-late (EEML).

Results: Irrespective of the arrhythmia mechanism, low bipolar voltage fractionated signals (0.14 ± 0.10 mV) were seen at the earliest activation site. The mean low-voltage area (LVA) at the earliest activation site was 3.2 ± 1.0 cm². EEML mapping revealed zones of conduction delay at the borders of LVAs.

Conclusions: LVAs protected by zones of slow conduction appears to play an important role in the initiation and maintenance of focal ATs.