The Combination of Pulmonary Vein Electrophysiology and Atrial Fibrosis Determines Driver Location

Abstract

Patients exhibit a range of pulmonary vein (PV) and fibrosis properties, but their individual and combined effects on arrhythmia inducibility and maintenance mechanisms is unknown. We aim to predict locations of high phase singularity (PS) density using a combination of PV electrophysiology and fibrosis measurements. We used a bilayer computational human atrial model with interstitial fibrosis based on delayed-enhancement MRI (DE-MRI), including high or low levels of fibrosis. PV action potential duration and conduction velocity were varied. Reentry was observed around the left atrial (LA)-PV junction in a subset of patients and reproduced in the model for PV properties with baseline APD, but not for short. For patients for whom rotors were located away from the PVs, increasing model fibrosis from low to high increased the model agreement with clinical PS density 2.3 ± 1.0 fold. For other patients, lower levels of fibrosis with baseline PV properties were more appropriate. These results suggest that modelling both PV electrophysiology and atrial fibrosis is important for determining arrhythmia mechanisms. The combined use of PV and DE-MRI measurements may improve ablation therapy success.

The electrophysiological characteristics of the initiation of atrial fibrillation from the pulmonary veins

“…A simulation test with a computational human atrial model revealed that the greatest AF inducibility could be found in cases with circular fibers at the PV ostium. 4,5 Dispersion of the ERP and the dynamic changes in the circumferential conduction delay within the PVs may lead to anisotropic conduction and reentry that can initiate AF. In this tissue of the journal, Kawai et al demonstrated that a circumferential intra-PV conduction delay arose at the onset of AF in response to a single extrastimulus at AF inducible sites.…”

“…Not only a longitudinal PV‐LA conduction delay but also a circumferential conduction delay contributes to AF initiation. A simulation test with a computational human atrial model revealed that the greatest AF inducibility could be found in cases with circular fibers at the PV ostium 4,5 . Dispersion of the ERP and the dynamic changes in the circumferential conduction delay within the PVs may lead to anisotropic conduction and reentry that can initiate AF.…”

Mechanisms of Arrhythmias in the Brugada Syndrome

“…This physiological variation in myofiber direction could, in theory, render the RVOT more vulnerable to myofiber disarray, particularly in the context of structural abnormalities. [ 25 , 26 ].…”

Location and coupling interval of an ectopic excitation determine the initiation of atrial fibrillation from the pulmonary veins

“…They also reported that fiber direction at the PV ostium was more complex and disorganized than that at the distal PV. Recently, simulation tests with computational human atrial model revealed that the greatest AF inducibility occurred for cases with circular fibers at the PV ostium 12,13 . Taken together, AF initiation would be determined by an initial anisotropic conduction in relations to location and CI of an ectopic excitation, and surrounding histological backgrounds.…”