Anatomic characteristics of the left atrial isthmus in patients with atrial fibrillation: Lessons from computed tomographic images

Shuo Ju Chiang, Hsuan Ming Tsao, Mei Han Wu, Ching Tai Tai, Shih Lin Chang, Wanwarang Wongcharoen, Yenn Jiang Lin, Li Wei Lo, Yi Jen Chen, Ming Huei Sheu, Cheng Yen Chang, Shih Ann Chen

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41 Citations (Scopus)

Abstract

Introduction: Left atrial (LA) isthmus ablation was reported to improve the success rate of catheter ablation of paroxysmal atrial fibrillation (AF). LA isthmus ablation could also cure a subset of LA flutter. Therefore, understanding the anatomy of the LA isthmus is important for performing the ablation effectively. Methods and Results: Group I included 45 patients (40 male, mean age = 50 ± 13 years) with paroxysmal AF who underwent catheter ablation. Group II included 45 patients (37 male, mean age = 54 ± 10 years) without a history of AF. They underwent a 16-slice multidetector computed tomography (MDCT) scan to delineate the LA structures before the ablation procedure. The average length of the LA isthmus was longer in group I than in group II (lateral isthmus: 3.30 ± 0.68 vs 2.71 ± 0.60 cm, P <0.001; medial isthmus: 5.12 ± 0.94 vs 4.45 ± 0.63 cm, P <0.001), and morphological patterns of lateral and medial isthmus were similar between groups. In addition, the average depth of lateral isthmus was similar between groups (0.62 ± 0.32 vs 0.55 ± 0.33 cm, P = 0.41), but the average depth of medial isthmus was larger in group I than in group II (0.60 ± 0.32 vs 0.44 ± 0.25 cm, P = 0.01). The medial isthmus had more ridges, as compared to the lateral isthmus (13% vs 0%, P = 0.026). Furthermore, the distances between esophagus and lateral isthmus were longer in group I than in group II (at the middle of isthmus and mitral annulus level: 21.0 ± 4.8 vs 18.4 ± 6.0 mm, P <0.001; and 37.1 ± 5.7 vs 29.6 ± 8.1 mm, P <0.001, respectively). Conclusion: The LA isthmus was longer in the AF patients. The morphology of the isthmus was variable. Compared with the lateral isthmus, the medial isthmus was longer and had more ridges. A peculiar configuration of the isthmus provided by CT images could influence the ablation strategy.

Original languageEnglish
Pages (from-to)1274-1278
Number of pages5
JournalJournal of Cardiovascular Electrophysiology
Volume17
Issue number12
DOIs
Publication statusPublished - Dec 2006

Keywords

  • Atrial fibrillation
  • Computed tomography
  • Isthmus

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology

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