Contemporary Outcomes and Factors Associated With Mortality After a Fetal or Neonatal Diagnosis of Ebstein Anomaly and Tricuspid Valve Disease.

BACKGROUND: Ebstein anomaly (EA) and tricuspid valve dysplasia (TVD) are rare anomalies and data on outcomes after a fetal or neonatal EA/TVD diagnosis are conflicting. METHODS: To examine the outcome and identify markers predictive of mortality, we reviewed our single-centre experience from 2000-2014. Variables were analyzed separately for cases diagnosed in utero without pregnancy termination and for all live-born patients. RESULTS: Of 47 fetal cases, 8 (17%) died in utero and 10 (21%) as neonates. Independent predictors associated with fetal demise included severe tricuspid regurgitation with a Doppler gradient < 40 mm Hg (odds ratio, 1.22 per mm Hg deduction; P = 0.003) and pulmonary regurgitation (odds ratio, 11.4; P = 0.03) at the baseline examination. A novel prognostic score (range, 0-10) combining the severity of 5 echocardiographic findings was independently associated with overall mortality (hazard ratio [HR], 1.39 per point increase; P = 0.01). Survival rates of 66 live births at 1 month, 1 year, and 5 years were 86%, 82%, and 80% respectively, and 75%, 60%, and 55% remained free from surgery at the same points in time. Factors associated with postnatal death in multivariate analysis included a younger gestational age at birth (HR per week, 1.59; P < 0.001), tricuspid annulus diameter (HR per z-score increase, 1.76; P = 0.004), and no pulmonary forward flow (HR, 4.63; P = 0.03). CONCLUSIONS: Our experience with fetal and neonatal EA/TVD shows better survival rates than previously reported. Mortality after a fetal diagnosis was significantly associated with hemodynamic changes indicative of a circular shunt, including pulmonary and tricuspid regurgitation severe enough to cause diastolic umbilical arterial flow reversal.

Fetal cardiac troponin isoforms rescue the increased Ca2+ sensitivity produced by a novel double deletion in cardiac troponin T linked to restrictive cardiomyopathy: a clinical, genetic, and functional approach.

A novel double deletion in cardiac troponin T (cTnT) of two highly conserved amino acids (Asn-100 and Glu-101) was found in a restrictive cardiomyopathic (RCM) pediatric patient. Clinical evaluation revealed the presence of left atrial enlargement and marked left ventricle diastolic dysfunction. The explanted heart examined by electron microscopy revealed myofibrillar disarray and mild fibrosis. Pedigree analysis established that this mutation arose de novo. The patient tested negative for six other sarcomeric genes. The single and double recombinant cTnT mutants were generated, and their functional consequences were analyzed in porcine skinned cardiac muscle. In the adult Tn environment (cTnT3 + cardiac troponin I), the single cTnT3-ΔN100 and cTnT3-ΔE101 mutations had opposing effects on the Ca(2+) sensitivity of force development compared with WT, whereas the double deletion cTnT3-ΔN100/ΔE101 increased the Ca(2+) sensitivity + 0.19 pCa units. In addition, cTnT3-ΔN100/ΔE101 decreased the cooperativity of force development, suggesting alterations in intrafilament protein-protein interactions. In the fetal Tn environment, (cTnT1 + slow skeletal troponin I), the single (cTnT1-ΔN110) and double (cTnT1-ΔN110/ΔE111) deletions did not change the Ca(2+) sensitivity compared with control. To recreate the patient's heterozygous genotype, we performed a reconstituted ATPase activity assay. Thin filaments containing 50:50 cTnT3-ΔN100/ΔE101:cTnT3-WT also increased the myofilament Ca(2+) sensitivity compared with WT. Co-sedimentation of thin filament proteins indicated that no significant changes occurred in the binding of Tn containing the RCM cTnT mutation to actin-Tm. This report reveals the protective role of Tn fetal isoforms as they rescue the increased Ca(2+) sensitivity produced by a cTnT-RCM mutation and may account for the lack of lethality during gestation.