Abstract
Introduction
Double-inlet left ventricle (DILV) is a rare form of a functionally univentricular heart typically managed through staged single-ventricle palliation. In selected patients with a hypoplastic but morphologically developed and functionally preserved right ventricle (RV), a 1.5 biventricular repair can be considered by septating the ventricles.
Case Info
A 5-month-old female with prenatally diagnosed DILV and S,D,S segmental anatomy. Preoperative transesophageal echocardiography demonstrated a large inlet ventricular septal defect, a small-to-moderate secundum atrial septal defect. The RV was moderately hypoplastic however demonstrated tripartite morphology, prominent trabeculation, significant hypertrophy, and preserved systolic function. Moderate pulmonary valve stenosis was also present, with a peak gradient of 42 mm Hg. Given the preserved RV morphology and function, a 1.5-ventricle strategy was selected. This entailed septating the ventricle with a 3mm fenestrated patch of the 18mm ventricular septal defect and bidirectional Glenn shunt. The ASD was closed primarily leaving a 3mm fenestration as well. Postoperative echocardiography demonstrated preserved RV and LV systolic function, good Glenn flow with additional antegrade pulmonary blood flow, and pulmonary valve gradient of 26mmHg. The postoperative course was complicated by complete heart block requiring permanent epicardial dual-chamber pacemaker placement on postoperative day 7. The patient’s postoperative saturations were greater than 95% on room air.
Disc Clinical
Although DILV is generally treated through a single-ventricle pathway, ventricular size alone may not fully characterize the functional potential of a hypoplastic RV. Assessment of RV morphology and systolic function may identify selected patients who are amenable to ventricular septation with or without a Glenn. In this patient, tripartite RV morphology supported the decision to pursue a 1.5 ventricular repair rather than perform a Glenn with a Pulmonary Artery (PA) band as would be done if single ventricle palliation was pursued. The addition of a bidirectional Glenn reduced systemic venous preload on the RV. It is anticipated that with future RV growth the VSD fenestration can be closed via a percutaneous route in the cauterization lab. The development of complete heart block illustrates the potential complexity of this approach to septet the heart.
Conclusion
A 1.5-ventricle repair may be a feasible alternative to conventional single-ventricle palliation in carefully selected patients with DILV and a hypoplastic but functional RV. Evaluation of RV morphology and function is critical to guide surgical strategy. Long-term follow-up is necessary to assess RV growth and function and to determine if the complications associated with long term Fontan physiology can be avoided.