Part one — Source: CTSNet Users Directory — ctsnet.org

Congenital listed as sole subspecialty · USA excluded · retrieved 26 Aug 2026

520 surgeons worldwide list congenital heart surgery as their only subspecialty.

The strictest reading of the CTSNet directory: surgeons whose profile names Congenital and nothing else, rather than Congenital alongside Cardiac or Thoracic. It is one sixth of the 3,348 who list congenital work in any form. The United States is excluded here and mapped separately below, from a different and more detailed source.

Subspecialty is self-selected on a membership profile, so an exclusive listing reflects how a surgeon describes their practice, not verified caseload. Argentina lists 27 of its 50 congenital surgeons as exclusive and Japan 52 of 139, against Turkey's 16 of 225 and India's 48 of 542 — differences that may owe as much to registration convention as to practice. A vermilion country means no exclusive listing in this directory, not an absence of care.

Part two — Source: Congenital Cardiology Today, Program Directory 2026–2027 — congenitalcardiologytoday.com

Congenital & paediatric cardiac care providers in North America · US section, pp. 5–37

The United States, by state

A different instrument entirely. Where the world map counts self-declared directory profiles, this counts named surgeons at named institutions in a curated programme directory — 293 surgeons across 128 programmes. Every surgeon is counted in exactly one state. The two maps are not on the same scale and should not be read as one gradient.

Every surgeon is counted once, in one state only. Many are listed at two or three institutions, and seventeen appear under programmes in two different states. Each was assigned to the programme where they hold a named leadership role or are the only surgeon listed, and otherwise to whichever listing comes first in the directory. Hawaii is the starkest case: of the six names attached to Kapi'olani, five are California-based. Two states have a programme but no named surgeon: Idaho, and New Jersey, where the directory prints “TBD”. Nine states list no programme at all. A red state means nobody in this directory — children in Wyoming or Vermont are referred across state lines, not left untreated.