Chamber-Specific Mitochondrial Remodeling In Atrial Fibrillation

Introduction: Studies have shown that right (RA) and left (LA) have different susceptibilities toward developing atrial fibrillation (AF). However, the molecular basis of these differences are not well characterized. Given these, we hypothesize that AF is associated with dissimilar energetic remodeling in the RA and LA and presence of interatrial differences might be a potential reason for different susceptibility of the atria to AF. Objective: The aim was to compare differences in mitochondrial oxidative phosphorylation system (OXPHOS) between the RA and LA in patients with and without AF (non-AF) and determine whether the same differences in chamber-specific sensitivity toward AF exist in the animal model of AF. Methods: The RA and LA tissue were collected from non-AF and AF dogs and consented patients undergoing elective open-heart surgery. Gene expression profiling of 72 genes involved in OXPHOS was performed using the Mitochondrial Energy Metabolism RT2 Profiler PCR Array. Comparison between the AF and non-AF groups were determined by using a pairwise differential expression analysis. A Venn diagram tool was applied to visualize expressed genes that overlap. Results: Expression of 14 and 25 genes was significantly reduced in the human and dog RA, correspondingly. Unlike, expression of only 2 and 9 genes was significantly reduced in human and dogs LA. The Venn diagram demonstrates the overlaps (common genes) and differences between the genes in patients and dogs with AF (Fig. A, B). Conclusion: AF is associated with different chamber-specific energetic remodeling suggesting that dissimilar mechanisms may contribute to the development and progression of AF.