A photo of Justin Tretter.

Pediatric Cardiologist, Imaging; Editor, Heart University

Assistant Professor, UC Department of Pediatrics


Board Certified

Make an Appointment

"In my practice, I always try to approach my patients with the same care and compassion I would want for my own children..."

About Me


I’m a pediatric cardiologist who specializes in noninvasive cardiac imaging, three-dimensional cardiac imaging and cardiovascular genetics. My unique additional training as a cardiac anatomist, under world-renowned cardiac anatomist Professor Robert Anderson from London, gives me exceptional insight as a cardiac imager.

I was drawn to a career in medicine when my grandfather, who was like a father to me, died of a brain tumor when I was a teenager. In college, I became fascinated with the cardiovascular system during a course in cardiopulmonary pathophysiology. My mother, who was an elementary school teacher, fueled my passion to work with children by involving me with her classes. All of this, along with the ability to provide lifesaving treatments and the fascinating anatomy and physiology of congenital heart disease, made pediatric cardiology a clear calling for me.

In my practice, I always try to approach my patients with the same care and compassion I would want for my own children, one of whom has a chronic illness. In our Cardiovascular Genetics Clinic within the Heart Institute, we have a unique multidisciplinary team. It includes cardiologists like me, our excellent genetic counselors and cardiovascular geneticists.

The purpose of my research is to understand detailed cardiac anatomy and function in order to improve cardiac imaging, interventions and outcomes. Much of my current research focuses on variation in the aortic root and how that impacts its function, as well as its relationship to the heart’s conduction system.

I also have led the development of Heart University, an online educational site for providers of congenital and pediatric acquired heart disease. I am the editor of this site, which has over 4,000 users spanning more than 125 countries and six continents, with an international editorial board.

In my spare time, I am very much a family man and love to spend time with my wife and three children. We are very active in our church. I also love to play basketball and coach my kids’ basketball teams. When I coach, I like to encourage children to be confident in their abilities, to work hard to reach their goals and not be afraid to make mistakes.

Clinical Interests

Pediatric cardiology; cardiac imaging; cardiac development and morphology

Academic Affiliation

Assistant Professor, UC Department of Pediatrics

Clinical Divisions

Cardiac MRI, Cardiovascular Genetics

My Locations

My Education

MD: St. George's University School, Grenada, West Indies.

Residency: University of Rochester, Rochester, NY.

Fellowship: New York University, New York, NY.

My Publications

Selected Publication

Atrial Function and Its Role in the Non-invasive Evaluation of Diastolic Function in Congenital Heart Disease. Ta, HT; Alsaied, T; Steele, JM; Truong, VT; Mazur, W; Nagueh, SF; Kutty, S; Tretter, JT. Pediatric Cardiology. 2020; 41:654-668.

Heart University: a new online educational forum in paediatric and adult congenital cardiac care. The future of virtual learning in a post-pandemic world?. Tretter, JT; Windram, J; Faulkner, T; Hudgens, M; Sendzikaite, S; Blom, NA; Hanseus, K; Loomba, RS; McMahon, CJ; Zheleva, B; et al. Cardiology in the Young. 2020; 30:560-567.

Effects of Normal Variation in the Rotational Position of the Aortic Root on Hemodynamics and Tissue Biomechanics of the Thoracic Aorta. Sundstrom, E; Jonnagiri, R; Gutmark-Little, I; Gutmark, E; Critser, P; Taylor, MD; Tretter, JT. Cardiovascular Engineering and Technology. 2020; 11:47-58.

Assessing the criteria for definition of perimembranous ventricular septal defects in light of the search for consensus. Tretter, JT; Tran, VH; Gray, S; Ta, H; Loomba, RS; O'Connor, W; Spicer, DE; Cook, AC; Anderson, RH. Orphanet Journal of Rare Diseases. 2019; 14.

Anatomical predictors of conduction damage after transcatheter implantation of the aortic valve. Tretter, JT; Mori, S; Anderson, RH; Taylor, MD; Ollberding, N; Truong, V; Choo, J; Kereiakes, D; Mazur, W. Open Heart. 2019; 6.

Risk Factors and Biomarkers of Poor Outcomes: Time to Throw Out Right Ventricular Volumes in Repaired Tetralogy of Fallot? Lessons From the INDICATOR Cohort. Tretter, JT; Redington, AN. Circulation. 2018; 138:2116-2118.

Variations in rotation of the aortic root and membranous septum with implications for transcatheter valve implantation. Tretter, JT; Mori, S; Saremi, F; Chikkabyrappa, S; Thomas, K; Bu, F; Loomba, RS; Alsaied, T; Spicer, DE; Anderson, RH. Heart. 2018; 104:999-1005.

Sudden death in Ebstein's anomaly: are we killing our patients with surgery?. Tretter, JT. European Heart Journal. 2018; 39:1978-1980.

The Forgotten Ventricle? The Left Ventricle in Right-Sided Congenital Heart Disease. Tretter, JT; Redington, AN. Circulation: Cardiovascular Imaging. 2018; 11.

The Significance of the Interleaflet Triangles in Determining the Morphology of Congenitally Abnormal Aortic Valves: Implications for Noninvasive Imaging and Surgical Management. Tretter, JT; Spicer, DE; Mori, S; Chikkabyrappa, S; Redington, AN; Anderson, RH. Journal of the American Society of Echocardiography. 2016; 29:1131-1143.