A ventricular septal defects (VSD) may be classified based on its location in the interventricular septum. The type of VSD has certain clinical implications.


Type: 1

Location: outflow of the right ventricle (RV), in the conal or outlet septum

Synonyms: conal, subpulmonary, infundibular, supracristal

Comment: higher frequency in Asians (33%) vs non-Asians (6%); spontaneous closure uncommon


Type: 2

Location: membranous septum, adjacent to the septal leaflet of the tricuspid valve and adjacent to the aortic valve

Synonyms: peri or paramembranous, conoventricular

Comment: most common defect (about 80%)


Type: 3

Location: lower part of the right ventricle, adjacent to the tricuspid valve

Synonyms: inlet

Comment: associated with Down's syndrome


Type: 4

Location: central, apical, anterior, posterior

Synonyms: muscular (surrounded by muscle)

Comment: spontaneous closure common; may be multiple


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