Atrial Macroreentry Tachycardia in Patients without Obvious Structural Heart Disease or Previous Cardiac Surgical or Catheter Intervention: Characterization of Arrhythmogenic Substrates, Reentry Circuits, and Results of Catheter Ablation

Authors


Address for correspondence: Martin Fiala, M.D., Ph.D., Department of Cardiology, Heart Center, Hospital Podlesí a.s., HraniČní 453, Třinec, 739 61, Czech Republic. Fax: +420 558304457; E-mail: martin.fiala@nempodlesi.cz

Abstract

Introduction: Atrial macroreentry tachycardia (AMRT) in patients without obvious structural heart disease or previous surgical or catheter intervention has not been characterized in detail.

Methods and Results: Electroanatomical mapping and ablation of right or left AMRT were performed in 33 patients. Right atrial central conduction obstacle was formed by an electrically silent area (ESA) in 15 (68%) patients and by a line of double potentials (DPs) in seven (32%) patients. Left atrial ESAs were found in all 11 patients with the left AMRT. Reentry circuit was reconstructed in 19 (86%) patients with right AMRT and seven (64%) patients with left AMRT. Of the ESA-related right AMRT, eight (50%) were double-loop reentry circuits utilizing a narrow critical isthmus within the ESA and eight (50%) were single-loop reentry circuits with a critical isthmus bounded by ESA and either ostium of the vena cava. Single-loop DP-related AMRTs had the critical isthmus between the DP line and the ostium of the inferior vena cava (IVC). Left AMRTs included a variety of single-, double-, or triple-loop reentry circuits and their critical isthmuses. During the 37 ± 15 month follow-up, atrial tachyarrhythmia-free clinical outcome was achieved in 21 (95%) patients (18 patients, 82%, without antiarrhythmic drugs) with the right AMRT and in nine (82%) patients (six patients, 55%, without antiarrhythmic drugs) with the left AMRT.

Conclusion: The majority of right and left AMRTs were related to the presence of ESA. Ablation can be successful with a favorable risk of atrial tachyarrhythmia recurrence.

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