Stability of scroll excitation waves in human atria during fibrillation: A computational study

Abstract

We computationally evaluated the functional roles of atrial fibrillation induced electrical remodelling (AFER)on IntroductionAtrial fibrillation (AF) affects the aged population and accounts for about 1% of the total National Health Service expenditure [1] in the UK alone and also has a large prevalence in the USA [2]. AF is the most common sustained arrhythmia leading to thromboembolism and heart failure among other debilitating cardiac complications. AF is characterized by irregular re-entrant electrical propagations in the atria. Chronic AF induced electrical remodeling (AFER) of membrane ionic channels in individual atrial cells has been recently studied in two experimental studies [3,4], and has been proposed as a major contributor underlying persistent as it shortens action potential duration (APD 90 ), reduces atrial conduction velocity (CV) leading to stability of reentrant excitation. In addition, anatomical obstacles due to the opening holes of blood vessels (e.g. superior vena cava (SVC) and pulmonary veins) may provide a secondary mechanism to sustain AF.In this paper, we studied the effects of AFER on the electrical activities in atrial cells and spatially extended atrial tissue. Dynamical behaviour of scroll waves in a 3D homogenous anatomical model were characterized. Our study has shown that AFER alone has a major effect on atrial conduction and scroll wave dynamics, which helps sustain AF. This study provides insights to understand how AF begets AF, by which paroxysmal AF transient to chronic AF due to AF-induced AFER.

Reentrant mechanisms triggered by ectopic activity in a three-dimensional realistic model of human atrium. a computer simulation study

“…The rotor was very regular and persisted in back wall for about 3000 ms. This result is agree with rotor hypothesis proposed by Jalife and with another experimental and computational studies [19,20], which have been obtained rotors in the atrium. After that, collisions and wave breaks were observed in back wall of both, left and right atrium (see figure 2 at 8920 ms, 9011 ms and 9443 ms).…”

Image‐based models of cardiac structure in health and disease

“…33 Although the model contains more anatomical detail than other existing models, the fiber orientations in the model were not measured but synthesized, using rule-based methods. 34 The same atrial model has been used in other studies [35][36][37] with some improvements in assigning fiber orientations. 35 To construct structural models of cardiac tissue at resolutions that approach or go below cardiomyocyte dimensions, optical imaging modalities including extended confocal microscopy and optical coherence tomography (OCT) have been used.…”