1. Department of Internal Medicine, Creighton University, Omaha, NE 68131, USA
2. Department of Internal Medicine, Seton Hall University School of Health and Medical Sciences, Trinitas Regional Medical Center, Elizabeth, NJ 07207, USA
3. Department of Cardiology, Ain Shams University, Cairo 11381, Egypt
4. Department of Cardiology, Creighton University, Omaha, NE 68131, USA