AVP and Myocardial fibrosis: The enhanced activity of AVP system, on the one hand, may suggest and predict a worse left ventricular function, with a consequent increased risk of life-threatening arrhythmias; on the other hand, it may have a direct pro-arrhythmogenic effect on myocardium, promoting myocardial fibrosis, and thus enhancing the electrical ventricular vulnerability [19].