Paroxysmal and persistent atrial fibrillation; does the clinical classification match the substrate?

Abstract

Abstract Background/Introduction The classification of atrial fibrillation (AF) currently is based on clinical characteristics, however classifying underlying electropathology would assist in selecting appropriate therapy. In this study, we measured atrial conduction parameters in sinus rhythm (SR) using an intra-operative high resolution epicardial mapping approach in paroxysmal (PAF) and persistent AF (persAF) patients. Purpose To study whether the clinical classification is related to the amount and severity of conduction disorders in SR. Methods We included 47 PAF and 24 persAF patients for intra-operative measurements of SR at the right atrium (RA), Bachmann's Bundle (BB), the left atrium (LA) and the pulmonary vein area (PV). Various conduction parameters were calculated, including number of continuous conduction delay and block (cCDCB) lines, total activation time (TAT), and orientation of conduction block (CB) lines at BB. Results After adjustment for confounders, only TAT of BB was significantly longer in persAF patients, 75 [53–92] ms vs 55 [40–76] ms. This can be attributed to more CB line parts orientated perpendicular to the conduction direction and a higher number of cCDCB lines. Other conduction characteristics at BB and other atrial areas showed no difference between PAF and persAF patients. Conclusion(s) Patients with persAF have a longer activation time at BB compared to patients with PAF. Other conduction parameters show significant overlap between these groups at BB and in other atrial areas, suggesting that, in SR, the clinical classification does not match the arrhythmogenic substrate. Funding Acknowledgement Type of funding source: None