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Right atrial tachycardia with 2:1 intra-atrial conduction

Masayoshi Kofune1, Ichiro Watanabe1, Yasuo Okumura1

  • 1Division of Cardiology, Department of Medicine, Nihon University School of Medicine, 30-1 Oyaguchi-kamimachi, Itabashi-ku, Tokyo 173-8610, Japan.

Journal of Arrhythmia
|September 4, 2015
PubMed

Insights

Atrial tachycardia (AT) with cycle length (CL) alternans showed variable conduction. Shorter CL alternans blocked conduction to the His bundle electrogram region and coronary sinus, impacting tachycardia maintenance.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Cardiac Arrhythmias

Background:

  • Atrial tachycardia (AT) is a significant arrhythmia.
  • Understanding the mechanisms of AT, especially those with complex electrophysiological behaviors like alternans, is crucial for effective treatment.
  • Inferolateral right atrium is a common origin for AT.

Purpose of the Study:

  • To describe a case of inferolateral right atrial tachycardia exhibiting cycle length (CL) alternans.
  • To analyze the conduction patterns during alternans to understand its impact on tachycardia maintenance.

Main Methods:

  • Case report of a patient with atrial tachycardia.
  • Intracardiac electrophysiological study including recording from high right atrium (HRA), His bundle electrogram region (HBE), and coronary sinus (CS).
  • Analysis of conduction during observed cycle length alternans.

Main Results:

  • Cycle length alternans was observed in an inferolateral right atrial tachycardia.
  • Conduction during the longer CL alternans was present to HRA, HBE, and CS.
  • Conduction during the shorter CL alternans was limited to the HRA, with block to the HBE and CS.

Conclusions:

  • Cycle length alternans in inferolateral right atrial tachycardia can lead to differential conduction block.
  • This pattern of conduction block during shorter CL alternans may contribute to the maintenance or termination of the tachycardia.
  • Further investigation into alternans mechanisms in AT is warranted.

Keywords:
2:1 Intra-atrial blockAblationAtrial tachycardia

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