SCN5A and obesity due to melanocortin 4 receptor deficiency: Diet-induced obesity resulted in increased arrhythmias and obesity-induced atrial remodeling (fibrosis, pathological hypertrophy, apoptosis) in WT mice, but phospho-ablation of Nav1.5 in the SA knock-in mice conferred resistance to obesity-induced arrhythmias and atrial remodeling.