IGFBP2 and atrial fibrillation: Based on the increased levels of IGFBP-2 in patients with hypertension and AF, and the data from other authors showing the expression of IGFBP-2 in hearts of rats with heart failure [36], we performed immunohistochemistry to determine the expression and localization of IGFBP-2 in the left atria of patients with AF at high risk of CE stroke.