Double inlet left ventricle

Double inlet left ventricle (DILV) describes a congenital cardiac anomaly in which both atrioventricular valves are associated with a single ventricle which demonstrates left ventricular morphology.

Epidemiology

This uncommon entity constituents 1% of all congenital cardiac anomalies, and is one of the more common variants of a univentricular heart ¹. 

Associations

• ventricular septal defect
• transposition of the great arteries
• subaortic stenosis

Pathology

Features include a single, dominant ventricle with an elliptical shape, smooth septal endocardium lacking associated papillary muscles, defining left ventricular morphology ³. Atrioventricular valves may lack sufficient anatomical features to define their morphology in mitral/tricuspid valves, and are commonly stenotic or hypoplastic. A rudimentary outflow chamber (right ventricle) may be identified at the cardiac base. The location of the septum may be left/anterior, defining the L-loop orientation, or right/anterior defining the less common D-loop orientation. Further classification is based upon the relation of the great arteries ¹:

• type I
  • normal arterial relations
• type II
  • rightward/anterior aortic location
• type III
  • leftward/anterior aortic location
• type IV
  • leftward/posterior aortic location