The right atrium affects in silico arrhythmia vulnerability in both atria

The role of the right atrium (RA) in atrial fibrillation (AF) has long been overlooked. Multiple studies have examined clinical conditions associated with AF, such as atrial enlargement, fibrosis extent, electrical remodeling, and wall thickening, but have been mainly concentrated on the left atrium (LA). AF research predominantly focuses on the LA because of 2 key paradigms. First, the well-established view that AF onset is primarily triggered by activity originating in the pulmonary veins of the LA.1 Second, comorbidities linked to AF, such as hypertension, valvular disease, and heart failure, primarily impact the left side of the heart, contributing to increased mortality and reduced quality of life. Thus, AF research continues to focus mostly on the LA, and, as a consequence, the role of the RA in AF is barely understood. With the advent of personalized medicine, patient-specific computer models of the atria are enhancing our understanding of intricate interactions during AF and have already been used to identify ablation targets, tailor ablation strategies, and predict recurrence in AF patients.2–5 Nevertheless, those methodologies did not specifically focus on the role of the RA, with some excluding RA tissue and others neglecting the assessment of AF induction or maintenance from RA sources. 
Computer models of the atria can aid in assessing how the RA influences arrhythmia vulnerability and in studying the role of RA drivers in the induction of AF, both aspects difficult to assess clinically and experimentally. This work assesses the “Creative Concept” of incorporating the RA in computational arrhythmia studies based on 1398 virtual pacing sequences in  8 biatrial and 8 monoatrial patient-specific models under 3 different substrate conditions, resulting in a total of 48 distinct model configurations.