It may be inherited, sporadic or acquired in utero
Features of Uhl’s anomaly:
(1) partial or complete absence of right ventricular myocardium
(2) apposition of the endocardium and epicardium of the right ventricle without intervening tissue, resembling parchment
(3) dyspnea and fatigue on exertion
(4) right ventricular dilatation with congestive heart failure
(5) variable arrhythmias or heart block
(6) variable regurgitation of a structurally normal pulmonic valve, especially during inspiration
(7) rarely other cardiac anomalies (pulmonary atresia, persistent ductus arteriosus, dysplasia of the tricuspid valve)
The pulmonary circulation is maintained by right atrial contraction.