Donald Hagler MD

Donald J. Hagler, Sr., MD, is a Professor of Medicine and Pediatrics at Mayo Clinic College of Medicine and Science and a distinguished pediatric cardiologist specializing in congenital heart disease and interventional pediatric cardiology. He serves as a consultant in the Division of Pediatric Cardiology and holds joint appointments in the Departments of Cardiovascular Medicine and Interventional Cardiology at Mayo Clinic.

Dr. Hagler has devoted more than five decades to advancing the diagnosis and minimally invasive treatment of congenital heart disease. His clinical expertise includes diagnostic and interventional congenital cardiac catheterization, transcatheter closure of atrial and ventricular septal defects, patent foramen ovale and patent ductus arteriosus closure, percutaneous pulmonary valve implantation, and advanced echocardiographic imaging, including fetal, transesophageal, and intracardiac echocardiography. He has played a pivotal role in developing catheter-based therapies that have significantly reduced the need for open-heart surgery in patients with congenital heart disease.

An internationally recognized clinician-scientist, Dr. Hagler's research focuses on interventional cardiac catheterization, structural heart interventions, congenital heart disease imaging, and innovative device therapies. He has authored hundreds of peer-reviewed publications and has contributed extensively to multicenter clinical trials evaluating transcatheter devices and congenital heart interventions.

Dr. Hagler earned his Doctor of Medicine from Saint Louis University School of Medicine before completing pediatric training at St. Louis University, followed by fellowships in pediatric cardiology at UCLA Medical Center and Mayo Clinic. He is board-certified in Pediatrics, Pediatric Cardiology, and Adult Congenital Heart Disease. Throughout his distinguished career, he has received numerous honors, including Mayo Clinic's Distinguished Pediatric Career Award, Distinguished Career Award, the 50-Year Service Award, and recognition as a Master of the Society for Cardiovascular Angiography and Interventions (MSCAI).