Portal de Periódicos da CAPES

How anatomy can guide ablation in isthmic atrial flutter

2008; Oxford University Press; Volume: 11; Issue: 1 Linguagem: Inglês

10.1093/europace/eun340

1532-2092

José Ángel Cabrera, S Y Ho, Damian Sánchez‐Quintana,

Cardiac pacing and defibrillation studies

Creation of a complete bidirectional conduction block across the inferior right atrial cavo-tricuspid isthmus is the accepted marker for long-term success in patients with isthmus-dependent atrial flutter.1,2 However, it may be extremely difficult to achieve or its effect is temporary in some patients.3–5 Histopathologic findings have demonstrated that transmural ablation of the atrial wall is a prerequisite for success.6–8 Factors making it difficult to obtain a complete, transmural, and permanent ablation line across the inferior isthmus may be haemodynamic but also anatomical owing to the variable and complex endocardial geometry of the isthmic region, and the unpredictable content of atrial myocardium and fibro-fatty tissues at different locations of this atrial territory. The cavo-tricuspid isthmus is limited posteriorly by the Eustachian valve/ridge and anteriorly by the annular insertion of the septal leaflet of the triscuspid valve. Post-mortem and in vivo imaging examination in normal hearts and in patients with atrial flutter have pointed to the anatomic variability of the dimensions, endocardial geometry, and muscular architecture across the anatomic landmarks of the inferior right atrium and its impact as anatomic determinant for catheter ablation.9–17 As displayed in attitudinally orientation, the isthmus shows on its endocardial surface an irregular quadrilateral shape. The superior border of the quadrilateral is the paraseptal isthmus (so-called septal isthmus) extending between the septal insertion of the Eustachian valve just above or posterior to the orifice of the coronary sinus, and the most inferior paraseptal insertion of the tricuspid valve. The inferolateral border of the quadrilateral area contained pectinate muscles … *Corresponding author. Tel: +34 91 902151016; fax: +34 915183232. E-mail address : jacabrera.mad{at}quiron.es or jac11339{at}yahoo.co.uk