Horst Sievert, MD, is the Director of the CardioVascular Center Frankfurt, Sankt Katharinen, and the Department of Internal Medicine, Cardiology, and Vascular Medicine of the Sankt Katharinen Hospital in Frankfurt, Germany. He is also an Associate Professor of Internal Medicine/Cardiology at the University of Frankfurt. Dr Sievert became Director of the Department of Interventional Cardiology and Angiology of the Heart Center Rotenburg in 1990, Senior Consultant at the Bethanien Hospital in Frankfurt in 1993, and Director of the CardioVascular Center Frankfurt, Sankt Katharinen in 2003. He has been the principal investigator in a number of clinical trials and has authored more than 130 manuscripts and 500 abstracts in peer-reviewed journals and 50 books and book contributions. He has also delivered more than 450 invited lectures around the world. Dr Sievert has performed more than 16,000 percutaenous coronary interventions and 6,000 peripheral angioplasties. His research is focused on highly specialized non-coronary interventions for patients with congenital heart disease, carotid disease, or high risk of stroke. Dr Sievert was the first to close the left atrial appendage percutaneously. He has the largest experience worldwide in catheter closure of heart defects in adults and receives referrals from all over the world. Dr Sievert received his medical degree at the University of Frankfurt, Germany. After training in internal medicine, nephrology, and intensive care medicine, he completed a Fellowship in cardiology and vascular medicine under the direction of Dr Martin Kaltenbach.