In long-standing persistent/permanent, but not paroxysmal AF patients, the number of CD45+ cells/mm2 in the total atrial tissue, as well as in the myocardium and adipose tissue layers, was significantly higher in patients of over 75 years old compared with patients below 55 years old and with patients between 55 and 74 years old (Fig. 4a). The gene discussed is PTPRC; the disease is Paroxysmal atrial fibrillation.