The Art of Survival: A tale of two univentricular hearts who reached adulthood without surgery

Tóm tắt

Background: Univentricular hearts are rare and their morphological  heterogeneity  has sparked interests on its embryology, nomenclature, physiology and  hemodynamics.  The prognosis of uncorrected univentricular hearts is poor with patients rarely reaching adulthood and succumbing early to heart failure and sudden death.

Objectives: We aim to present two cases to demonstrate the diversity of univentricular heart presentations and delve into the  lessons of the hemodynamic and physiologic  adaptations  that contributed to their survival to the third decade of life without surgery.

Case: Sequential segmental analyses  disclosed RA to have situs ambiguous-heterotaxy syndrome-left isomerism while RM has situs solitus. RA has single atrium and single right ventricle while RM a “single atrium physiology” (tricuspid atresia and non-restrictive ASD secundum) and a single left ventricle.  Both have a single inlet atrioventricular connection and  concordant (RM) and  double outlet (RA) ventriculo-arterial connections. RM has a subpulmonic stenosis while RA has a narrowed RV outflow tract. Both have a persistent left SVC.

Discussion: The admixing of oxygenated pulmonary venous return  and  oxygen replete blood  from systemic circulation at the atrial level, the protective  right outflow tract obstruction  preventing pulmonary over circulation  and just the right amount of major aorto-pulmonary collaterals  as alternative sources of pulmonary flow provided hemodynamic and physiologic  adaptations for survival.  

Conclusion: Herein we report two cases that epitomize the diversity and complexity of univentricular hearts. Maintenance of a “balanced physiology” enable a minority of them to survive despite the unfavorable hemodynamics of a univentricular heart.