Ventricular hypertrophy as a risk factor in ventricular septation for double-inlet left ventricle

Ventricular septation for double inlet left ventricle

Ventricular septation is a biventricular repair for certain types of functionally univentricular hearts. Double inlet left ventricle (DILV) is one type of functionally univentricular heart which in certain instances is amenable to ventricular septation. Thirty-four patients underwent ventricular septation for DILV from 1971 to 2000. Hospital death occurred in seven and late death in two. Mean follow-up period was 15 years. Actuarial survival rate was 73.3% (24 patients) at 15 years, 73.3% (15 patients) at 20 years, 73.3% (five patients) at 25 years, and 73.3% (one patient) at 30 to 40 years. Ventricular septation is an alternative to Fontan operation for selected patients with single ventricle, DILV.

Septation of the single ventricle: revisited

BACKGROUND

Septation of a single ventricle into 2 functioning ventricles can provide an alternative to the Fontan operation. However, early experiences with septation reported unacceptable morbidity and mortality. The present study selected only those patients with large volume-overloaded hearts, 2 well-functioning atrioventricular valves, and an absence of severe outlet obstruction. Early and intermediate outcomes are evaluated.

METHODS AND RESULTS

Between June 1990 and March 1999, 11 patients underwent septation in 1 or 2 stages. Diagnoses of the patients included double-inlet left ventricle in 9, double-inlet right ventricle in 1 patient, and indeterminate ventricle in 1 patient. Five had l-transposition and 3 had d-transposition of the great arteries. Six had septation as 1 stage, 5 as planned 2-stage operations (2/5 completed). The median age for septation in 1 stage was 2.1 years (range 4 months to 5.8 years); for 2 stages, the median age was 7.2 months (range 3 to 14 months). Median follow-up time was 2.3 years. Eight of 11 patients survived (73%), with 2 early deaths and 1 late death. Seven of the 8 survivors have undergone complete septation (5 as single stage, 2 as 2 stages). Complications included surgically induced complete atrioventricular block in 1 patient and significant residual ventricular septal defects in another. Qualitatively, left ventricular function by echocardiography is normal in all patients, whereas right ventricular function is mildly decreased in 1 patient. All patients are clinically well.

CONCLUSION

The septation procedure for single ventricle hearts may be a reasonable alternative to the Fontan operation in selected patients.

Which hearts are unsuitable for biventricular correction?

BACKGROUND

The surgical option of biventricular repair requires two ventricles, each fully capable of supporting the systemic or pulmonary circulation. The morphologic substrates that may preclude some hearts from biventricular repair need to be assessed.

METHODS

Heart specimens were reviewed to assess the morphologic mechanisms that produce an unbalanced ventricular mass and to identify features that would, potentially, be a contraindication for biventricular repair.

RESULTS

Hearts with solitary and indeterminate ventricles, and hearts with essentially solitary ventricles, often have associated abnormalities of venoatrial connections and arrangement of the atrioventricular valves. In the majority of hearts with univentricular atrioventricular connections, the rudimentary and incomplete ventricle of either right or left morphology may be too small to support either the systemic or the pulmonary circulation. Straddling with overriding of the atrioventricular valve, unbalanced atrioventricular septal defect, and gross hypoplasia of one of the ventricles in hearts with biventricular connections are other mechanisms producing ventricular imbalance, which could preclude biventricular repair.

CONCLUSIONS

The morphologic mechanisms that result in ventricular imbalance are mainly related to the sizes and morphology of the ventricles, septal malalignment, valvar morphology, and component make-up of the ventricles. These features will influence decision-making in considering the option of biventricular repair.