Dr. Nielsen obtained an undergraduate degree in chemistry from the University of North Carolina in 1986. He received his M.D. degree from Bowman Gray School of Medicine at Wake Forest in 1990. He did his Internal Medicine and Cardiology training at the Medical University of South Carolina. After completing his training, Dr. Nielsen practiced Cardiology in Columbia, South Carolina for two years before returning to MUSC as a faculty member in 1998. Dr. Nielsen's clinical and research interests include: complex coronary artery intervention, acute coronary syndromes, alcohol septal ablation for hypertrophic obstructive cardiomyopathy, percutaneous closure of atrial septal defect and patent foramen ovale, coronary CT angiography, renal artery stenosis.