Aortopulmonary window associated with criss-cross heart: a rare and complex neonatal presentation

BACKGROUND: Aortopulmonary window is an uncommon CHD that often coexists with additional cardiovascular anomalies. Criss-cross heart, defined by rotation of the ventricular mass with crossed atrioventricular inflow streams, is exceedingly rare. The coexistence of aortopulmonary window and criss-cross heart is exceptional and markedly increases diagnostic and therapeutic complexity. CASE SUMMARY: We report a full-term neonate with prenatal suspicion of aortopulmonary window. Postnatal echocardiography and CT demonstrated situs solitus, concordant atrioventricular and ventriculoarterial connections, rotational malalignment of the ventricles consistent with criss-cross heart, an inferior sinus venosus atrial septal defect, and a large type III aortopulmonary window. There was marked right-sided dilation and evolving right ventricular dysfunction, although no interrupted aortic arch was identified. At 17 days of life, the patient underwent early surgical repair with reconstruction of the aortic pathway. Despite anatomically successful correction, the immediate postoperative course was complicated by severe ventricular dysfunction and refractory low cardiac output syndrome, requiring venoarterial extracorporeal membrane oxygenation for haemodynamic stabilisation. Extracorporeal membrane oxygenation was discontinued on day nine, and follow-up imaging showed preserved biventricular systolic function and no residual aortopulmonary window. CONCLUSION: This case illustrates an exceptionally rare association between aortopulmonary window and criss-cross heart, underscoring the value of prenatal detection and detailed postnatal imaging to delineate complex anatomical relationships. Early surgical intervention was mandatory, and the need for extracorporeal membrane oxygenation highlights the high intrinsic risk of this anatomical combination. Reporting such cases expands the limited literature on rare congenital cardiac malformations and may inform future refinements in diagnostic evaluation and perioperative management.