Cardiac electrical substrate mapping in isolated rabbit hearts ongoing atrial fibrillation

• Grant number: 24/08071-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2025
• End date: February 28, 2027
• Field of knowledge: Engineering - Biomedical Engineering - Bioengineering
• Principal Investigator: João Loures Salinet Júnior
• Grantee: Mouhamed Zakiou Kolawole Adissa Raimi
• Host Institution: Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas (CECS). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Associated research grant: 18/25606-2 - Accurate mapping of cardiac fibrillation activity: an experimental contribution, AP.JP

Abstract

Atrial fibrillation (AF) is the most common cardiac arrhythmia with significant morbidity. Structural remodeling and fibrosis play key roles in AF pathogenesis, but the precise molecular mechanisms remain incompletely understood. This study aims to map the distribution and extent of interstitial fibrosis in left and right atria from rabbits with electrically induced AF using an integrated experimental approach. AF will be induced in isolated perfused rabbit hearts through burst pacing following cholinergic stimulation. Epicardial optical mapping of electrical activity will be performed using voltage-sensitive dyes and a panoramic imaging system. Contact electrogram mapping will complement the optical data. 3D surface imaging will reconstruct atrial anatomy. AF induction, mapping and imaging will be optimized through iterative experiments. Atrial tissues will then be studied to characterize fibrosis using histology, immunohistochemistry, second harmonic generation microscopy and spectroscopic techniques. Quantitative image analysis will measure parameters like collagen coverage, fiber thickness and myofibroblast counts. Differences between AF and control groups will be evaluated by statistical comparisons. This study will generate high-resolution panoramic maps of electrical activation and fibrosis distribution in the atrial myocardium of rabbits with AF. By correlating structural and electrophysiological remodeling, the multimodal mapping approach can provide insights into mechanisms of AF occurrence, maintenance, and progression. Characterization in the rabbit model can enable translation into clinical diagnostic and therapeutic strategies against atrial fibrillation.