1. Post Graduate Medical School, University of Palermo, Palermo, Italy
2. School of Medicine, Mater Misericordiae University Hospital and Children’s Health at Crumlin, University College of Dublin, Dublin, Ireland
3. Division of Cardiology, Department of Systems Medicine, Tor Vergata University, Rome, Italy
4. Division of Cardiology, University of Arkansas for Medical Sciences and the VA Medical Center, Little Rock, AR, USA