Matthew O'Brien, MD

Matthew O’Brien, MD, is a pediatric cardiologist who cares for children with a wide range of heart conditions, including congenital heart disease. He is devoted to helping his patients live longer, healthier lives with fewer complications and collaborates with surgical, interventional cardiology, and electrophysiology teams to create treatment plans tailored to each child’s needs. “What I like to tell families is that our job as cardiologists is to help children function at the highest level of exercise or activity they wish to reach,” Dr. O’Brien says.

“What I find so interesting and exciting about pediatric cardiology,” he continues, “is that there are still so many unanswered questions, and so many ways we can continue to improve care for children with congenital heart disease. We often see uncommon or rare forms of structural heart disease in children, and we always rely on close communication and shared decision-making among the whole care team—and, most importantly, with the patient and family—to help kids thrive.”

As an instructor in pediatrics (cardiology) at Yale School of Medicine, Dr. O’Brien’s research explores how genetic variations influence the development and outcomes of complex congenital heart conditions, especially hypoplastic left heart syndrome. Supported by an American Heart Association postdoctoral fellowship and mentored by Martina Brueckner, MD, he uses large-scale genomic data to investigate how certain changes in genes may increase a child’s risk of severe heart failure or other complications. He is also dedicated to advancing clinical informatics and medical education, with the aim of bringing personalized, genetics-informed approaches into everyday cardiac care.

Dr. O’Brien received his medical training from the Frank H. Netter School of Medicine at Quinnipiac University, followed by a pediatric residency and pediatric cardiology fellowship at Yale New Haven Children’s Hospital. In his personal time, he enjoys spending time outdoors with his partner and their two Samoyed dogs.