Matthew Hurles and colleagues report exome sequencing of 1,891 individuals with syndromic or nonsyndromic congenital heart defects (CHD). They found that nonsyndromic CHD patients were enriched for protein-truncating variants in CHD-associated genes inherited from unaffected parents and identified three new syndromic CHD disorders caused by de novo mutations. Congenital heart defects (CHDs) have a neonatal incidence of 0.8–1% (refs. 1,2). Despite abundant examples of monogenic CHD in humans and mice, CHD has a low absolute sibling recurrence risk (∼2.7%)3, suggesting a considerable role for de novo mutations (DNMs) and/or incomplete penetrance4,5. De novo protein-truncating variants (PTVs) have been shown to be enriched among the 10% of 'syndromic' patients with extra-cardiac manifestations6,7. We exome sequenced 1,891 probands, including both syndromic CHD (S-CHD, n = 610) and nonsyndromic CHD (NS-CHD, n = 1,281). In S-CHD, we confirmed a significant enrichment of de novo PTVs but not inherited PTVs in known CHD-associated genes, consistent with recent findings8. Conversely, in NS-CHD we observed significant enrichment of PTVs inherited from unaffected parents in CHD-associated genes. We identified three genome-wide significant S-CHD disorders caused by DNMs in CHD4, CDK13 and PRKD1. Our study finds evidence for distinct genetic architectures underlying the low sibling recurrence risk in S-CHD and NS-CHD.

Background— Left ventricular noncompaction constitutes a primary cardiomyopathy characterized by a severely thickened, 2-layered myocardium, numerous prominent trabeculations, and deep intertrabecular recesses. The genetic basis of this cardiomyopathy is still largely unresolved. We speculated that mutations in sarcomere protein genes known to cause hypertrophic cardiomyopathy and dilated cardiomyopathy may be associated with left ventricular noncompaction. Methods and Results— Mutational analysis in a cohort of 63 unrelated adult probands with left ventricular noncompaction and no other congenital heart anomalies was performed by denaturing high-performance liquid chromatography analysis and direct DNA sequencing of 6 genes encoding sarcomere proteins. Heterozygous mutations were identified in 11 of 63 samples in genes encoding β-myosin heavy chain ( MYH7 ), α-cardiac actin ( ACTC ), and cardiac troponin T ( TNNT2 ). Nine distinct mutations, 7 of them in MYH7 , 1 in ACTC , and 1 in TNNT2 , were found. Clinical evaluations demonstrated familial disease in 6 of 11 probands with sarcomere gene mutations. MYH7 mutations segregated with the disease in 4 autosomal dominant LVNC kindreds. Six of the MYH7 mutations were novel, and 1 encodes a splice-site mutation, a relatively unique finding for MYH7 mutations. Modified residues in β-myosin heavy chain were located mainly within the ATP binding site. Conclusions— We conclude that left ventricular noncompaction is within the diverse spectrum of cardiac morphologies triggered by sarcomere protein gene defects. Our findings support the hypothesis that there is a shared molecular etiology of different cardiomyopathic phenotypes.

Aims Correct timing of pulmonary valve replacement (PVR) is crucial for preventing complications of pulmonary regurgitation and right ventricular (RV) dilatation after repair of tetralogy of Fallot. We sought to assess the remodelling of the RV after early PVR in children, using cardiovascular magnetic resonance (CMR). Methods and results Twenty children with severe pulmonary regurgitation and RV dilatation and mean age 13.9±3 years underwent CMR evaluation 5.6±1.8 months before and 5.9±0.6 months after PVR. PVR was performed when the RV end-diastolic volume exceeded 150 mL/m², as measured by CMR. The time interval between primary repair and PVR was 12±3 years. Post-operative CMR demonstrated a significant reduction of the RV end-diastolic volume from 189.8±33.4 to 108.7±25.8 mL/m² (P<0.0001), of the RV end-systolic volume from 102.4±27.3 to 58.2±16.3 mL/m² (P<0.0001), and of the RV mass from 48.7±12.3 to 35.8±7.7 g/m² (P<0.0001). The RV ejection fraction did not change significantly. Conclusion Prompt RV remodelling, with reduction of RV volume and mass, is observed after performing PVR if the RV end-diastolic volume exceeds 150 mL/m². Early PVR may prevent the detrimental complications of severe pulmonary regurgitation.

Dysfunction of valved conduits in the right ventricular outflow tract (RVOT) limits durability and enforces repeated surgical interventions. We report on our combined two-centre experience with percutaneous pulmonary valve implantation (PPVI). One hundred and two patients with RVOT dysfunction [median weight: 63 kg (54.2–75.9 kg), median age: 21.5 years (16.2–30.1 years), diagnoses: TOF/PA 61, TAC 14, TGA 9, other 10, AoS post-Ross-OP 8] were scheduled for PPVI since December 2006. Percutaneous pulmonary valve implantation was performed in all patients. Pre-stenting of the RVOT was done in 97 patients (95%). The median peak systolic RVOT gradient decreased from 37 mmHg (29–46 mmHg) to 14 mmHg (9–17 mmHg, P < 0.001) and the ratio RV pressure/AoP decreased from 62% (53–76%) to 36% (30–42%, P < 0.0001). The median end-diastolic RV-volume index (MRI) decreased from 106 mL/m² (93–133 mL/m²) to 90 mL/m² (71–108 mL/m², P = 0.001). Pulmonary regurgitation was significantly reduced in all patients. One patient died due to compression of the left coronary artery. The incidence of stent fractures was 5 of 102 (5%). During follow-up [median: 352 days (99–390 days)] one percutaneous valve had to be removed surgically 6 months after implantation due to bacterial endocarditis. In 8 of 102 patients, a repeated dilatation of the valve was done due to a significant residual systolic pressure gradient, which resulted in a valve-in-valve procedure in four. This study shows that PPVI is feasible and it improves the haemodynamics in a selected patient collective. Apart from one coronary compression, the rate of complications at short-term follow-up was low. Percutaneous pulmonary valve implantation can be performed by experienced interventionalists with similar results as originally published. The intervention is technically challenging and longer clinical follow-up is needed.

Background—: Off-label use of transcatheter aortic and pulmonary valve prostheses for tricuspid valve-in-valve implantation (TVIV) within dysfunctional surgical tricuspid valve (TV) bioprostheses has been described in small reports. Methods and Results—: An international, multicenter registry was developed to collect data on TVIV cases. Patient-related factors, procedural details and outcomes, and follow-up data were analyzed. Valve-in-ring or heterotopic TV implantation procedures were not included. Data were collected on 156 patients with bioprosthetic TV dysfunction who underwent catheterization with planned TVIV. The median age was 40 years, and 71% of patients were in New York Heart Association class III or IV. Among 152 patients in whom TVIV was attempted with a Melody (n=94) or Sapien (n=58) valve, implantation was successful in 150, with few serious complications. After TVIV, both the TV inflow gradient and tricuspid regurgitation grade improved significantly. During follow-up (median, 13.3 months), 22 patients died, 5 within 30 days; all 22 patients were in New York Heart Association class III or IV, and 9 were hospitalized before TVIV. There were 10 TV reinterventions, and 3 other patients had significant recurrent TV dysfunction. At follow-up, 77% of patients were in New York Heart Association class I or II ( P <0.001 versus before TVIV). Outcomes did not differ according to surgical valve size or TVIV valve type. Conclusions—: TVIV with commercially available transcatheter prostheses is technically and clinically successful in patients of various ages across a wide range of valve size. Although preimplantation clinical status was associated with outcome, many patients in New York Heart Association class III or IV at baseline improved. TVIV should be considered a viable option for treatment of failing TV bioprostheses.