Atrial Stretch in Patients with Paroxysmal Junctional Tachycardias and Atrial Fibrillation but Structurally Normal Heart

Abstract

to comparatively assess echographic indicators of atrial dilatation and decremental intra and interatrial and conduction in patients (pts) presenting junctional reentrant tachycardias (JT) with or without paroxysmal atrial fibrillation (pAF). 58 pts without structural heart disease, referred to electrophysiological study which underwent ablation for JT were studied; 26 pts aged 41±10 years with pAF episodes/ inducible AF, were compared to 32 control-matched JT pts aged 39±12 years. Parameters: left atrial dimensions (LAd = M-mode, parasternal, LAt and LAl are measurements of short and long-axis apical four chamber view), surface (LAs), volume (LAv using ellipse formula), right atrial surface (RAs), total atrial surface (TAs = LAs+RAs). Decremental index (DI) was calculated as maximum percent prolongation of interatrial conduction time (iaCT) during S2 and S3 delivery. there was no difference between the 2 groups concerning baseline iaCT (59±21 ms vs 53±18 ms p = 0.08), LAd (p = 0.08) and LAt (p = 0.09) while the following parameters were significantly higher in pAF pts: LAl: 5.0±0.5 vs 4.5±0.3cm, (p = 0.001); LAs: 19.6±5.7 vs 16.3±2.1cm2, (p = 0.001); TAs: 35.6±6.9 vs 27.6±5.1 cm2 (p = 0.0001); LAv: 46.6±10.4 vs 37.2±9.3 ml, (p = 0.0001); DI: 41±17% vs 24±14% (p = 0.001). In pAF group, atrial fragmentation and atrial double potentials were recorded in 23 pts. No control pts had this evidence. this study supports the role of atrial stretch in the genesis of AF in pts with junctional tachycardias. Further studies need to investigate the relation between burden of tachycardia and atrial stretch in a larger population.