Reduction of Conduction Velocity in Patients with Atrial Fibrillation.

Annejet Heida,Ad J J C Bogers,Natasja M S De Groot,Yannick J H J Taverne,Willemijn F B Van Der Does,Mathijs S Van Schie

doi:10.3390/jcm10122614

Abstract

It is unknown to what extent atrial fibrillation (AF) episodes affect intra-atrial conduction velocity (CV) and whether regional differences in local CV heterogeneities exist during sinus rhythm. This case-control study aims to compare CV assessed throughout both atria between patients with and without AF. Patients (n = 34) underwent intra-operative epicardial mapping of the right atrium (RA), Bachmann’s bundle (BB), left atrium (LA) and pulmonary vein area (PVA). CV vectors were constructed to calculate median CV in addition to total activation times (TAT) and unipolar voltages. Biatrial median CV did not differ between patients with and without AF (90 ± 8 cm/s vs. 92 ± 6 cm/s, p = 0.56); only BB showed a CV reduction in the AF group (79 ± 12 cm/s vs. 88 ± 11 cm/s, p = 0.02). In patients without AF, there was no predilection site for the lowest CV (P5) (RA: 12%; BB: 29%; LA: 29%; PVA: 29%). In patients with AF, lowest CV was most often measured at BB (53%) and ranged between 15 to 22 cm/s (median: 20 cm/s). Lowest CVs were also measured at the LA (18%) and PVA (29%), but not at the RA. AF was associated with a prolonged TAT (p = 0.03) and decreased voltages (P5) at BB (p = 0.02). BB was a predilection site for slowing of conduction in patients with AF. Prolonged TAT and decreased voltages were also found at this site. The next step will be to determine the relevance of a reduced CV at BB in relation to AF development and maintenance.

Highlights

Intra-atrial conduction velocity (CV) is determined by ion channel properties, cellto-cell coupling, wavefront geometry and muscle thickness [1,2]
CV was reduced in the atrial fibrillation (AF) group only at Bachmann’s Bundle (BB)
The variance of CV was comparable between both groups at this site

Summary

Introduction

Intra-atrial conduction velocity (CV) is determined by ion channel properties, cellto-cell coupling, wavefront geometry and muscle thickness [1,2]. In 12 patients with ischemic heart disease or Wolff–Parkinson–White syndrome who underwent cardiac surgery, the average CV measured during sinus rhythm (SR) at the right atrial free wall in an area of 3 × 4 cm was 88 cm/s [4]. There is only one report on comparison of CV during SR between patients with and without AF [6]. In this endocardial mapping study, paroxysmal AF was associated with a reduction of CV to 60 ± 12 cm/s at the right atrium (RA) and to 51 ± 11 cm/s at the left atrium (LA) compared to patients with atrioventricular nodal re-entrant tachycardia and Wolff–

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Results

Conclusion