Clinical Presentation and Heart Failure in Children With Arrhythmogenic Cardiomyopathy

International audienceBackground: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease, and sudden cardiac death represents an important mode of death in these patients. Data evaluating the implantable cardioverter defibrillator (ICD) in this patient population remain scarce. Methods: A Nationwide French Registry including all patients with tetralogy of Fallot with an ICD was initiated in 2010 by the French Institute of Health and Medical Research. The primary time to event end point was the time from ICD implantation to first appropriate ICD therapy. Secondary outcomes included ICD-related complications, heart transplantation, and death. Clinical events were centrally adjudicated by a blinded committee. Results: A total of 165 patients (mean age, 42.2±13.3 years, 70.1% males) were included from 40 centers, including 104 (63.0%) in secondary prevention. During a median (interquartile range) follow-up of 6.8 (2.5–11.4) years, 78 (47.3%) patients received at least 1 appropriate ICD therapy. The annual incidence of the primary outcome was 10.5% (7.1% and 12.5% in primary and secondary prevention, respectively; P =0.03). Overall, 71 (43.0%) patients presented with at least 1 ICD complication, including inappropriate shocks in 42 (25.5%) patients and lead dysfunction in 36 (21.8%) patients. Among 61 (37.0%) patients in primary prevention, the annual rate of appropriate ICD therapies was 4.1%, 5.3%, 9.5%, and 13.3% in patients with, respectively, 0, 1, 2, or ≥3 guidelines-recommended risk factors. QRS fragmentation was the only independent predictor of appropriate ICD therapies (hazard ratio, 3.47 [95% CI, 1.19–10.11]), and its integration in a model with current criteria increased the 5-year time-dependent area under the curve from 0.68 to 0.81 ( P =0.006). Patients with congestive heart failure or reduced left ventricular ejection fraction had a higher risk of nonarrhythmic death or heart transplantation (hazard ratio, 11.01 [95% CI, 2.96–40.95]). Conclusions: Patients with tetralogy of Fallot and an ICD experience high rates of appropriate therapies, including those implanted in primary prevention. The considerable long-term burden of ICD-related complications, however, underlines the need for careful candidate selection. A combination of easy-to-use criteria including QRS fragmentation might improve risk stratification. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03837574

Contribution of exome sequencing for genetic diagnostic in arrhythmogenic right ventricular cardiomyopathy/dysplasia

International audienceBackground: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D) is an inherited cardiomyopathy mainly caused by heterozygous desmosomal gene mutations, the major gene being PKP2. The genetic cause remains unknown in ~50% of probands with routine desmosomal gene screening. The aim of this study was to assess the diagnostic accuracy of whole exome sequencing (WES) in ARVC/D with negative genetic testing.Methods: WES was performed in 22 patients, all without a mutation identified in desmosomal genes. Putative pathogenic variants were screened in 96 candidate genes associated with other cardiomyopathies/channelopathies. The sequencing coverage depth of PKP2, DSP, DSG2, DSC2, JUP and TMEM43 exons was compared to the mean coverage distribution to detect large insertions/deletions. All suspected deletions were verified by real-time qPCR, Multiplex-Ligation-dependent-Probe-Amplification (MLPA) and cGH-Array. MLPA was performed in 50 additional gene-negative probands.Results: Coverage-depth analysis from the 22 WES data identified two large heterozygous PKP2 deletions: one from exon 1 to 14 and one restricted to exon 4, confirmed by qPCR and MLPA. MLPA identified 2 additional PKP2 deletions (exon 1–7 and exon 1–14) in 50 additional probands confirming a significant frequency of large PKP2 deletions (5.7%) in gene-negative ARVC/D. Putative pathogenic heterozygous variants in EYA4, RBM20, PSEN1, and COX15 were identified in 4 unrelated probands.Conclusion: A rather high frequency (5.7%) of large PKP2 deletions, undetectable by Sanger sequencing, was detected as the cause of ARVC/D. Coverage-depth analysis through next-generation sequencing appears accurate to detect large deletions at the same time than conventional putative mutations in desmosomal and cardiomyopathy-associated genes

High risk of heart failure associated with desmoglein-2 mutations compared to plakophilin-2 mutations in arrhythmogenic right ventricular cardiomyopathy/dysplasia

International audienceBACKGROUND:Previous studies suggested that genetic status affects the clinical course of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) patients. The aim of this study was to compare the outcome of desmoglein-2 (DSG2) mutation carriers to those who carry the plakophilin-2 (PKP2) mutation, the most common ARVC/D-associated gene.METHODS AND RESULTS:Consecutive ARVC/D patients carrying a pathogenic mutation in PKP2 or DSG2 were selected from a national ARVC/D registry. The cumulative freedom from sustained ventricular arrhythmia and cardiac transplantation/death from heart failure (HF) during follow-up was assessed, compared between PKP2 and DSG2, and predictors for ventricular arrhythmia and HF events determined. Overall, 118 patients from 78 families were included: 27 (23%) carried a DSG2 mutation and 91 (77%) a PKP2 mutation. There were no significant differences between DSG2 and PKP2 mutation carriers concerning gender, proband status, age at diagnosis, T-wave inversion, or right ventricular dysfunction at baseline. DSG2 patients displayed more frequent epsilon wave (37% vs. 17%, P = 0.048) and left ventricular dysfunction at diagnosis (54% vs. 10%, P < 0.001). During a median follow-up of 5.6 years (2.5-16), DSG2 and PKP2 mutation carriers displayed a similar risk of sustained ventricular arrhythmia (log-rank P = 0.20), but DSG2 mutation carriers were at higher risk of transplantation/HF-related death (log-rank P < 0.001). The presence of a DSG2 mutation vs. PKP2 mutation was a predictor of transplantation/HF-related death in univariate Cox analysis (P = 0.0005).CONCLUSIONS:In this multicentre cohort, DSG2 mutation carriers were found to be at high risk of end-stage HF compared to PKP2 mutation carriers, supporting careful haemodynamic monitoring of these patients. The benefit of early HF treatment needs to be assessed in DSG2 carriers

Pedigree and qPCR results from family A and U.

<p>qPCR showed a ~50% reduction of exon 4 <i>PKP2</i> DNA in affected individuals A.1, A.2 and A3 compared to the healthy father A.4 (used as a control). <i>PKP2</i> DNA quantification was normal in exon 3 and 5 for all individuals. In family U, qPCR showed a 50% reduction of <i>PKP2</i> DNA in exon 4 and 13 in affected individuals U.1 and U.2 and their mother U.3 whereas it was comparable to controls in father U.4. Individuals U.1 and U.2 also carried the p.Gly712Arg (G712R) rare <i>PKP2</i> variant that falsely appeared in the Sanger chromatogram as homozygous (HmZ) instead of hemizygous because of the absence of the other <i>PKP2</i> allele. This variant was inherited from the father, in absence of familial history of consanguinity, in whom it appeared heterozygous(Htz).</p

Hemolysis indexes for biochemical tests and immunoassays on Roche analyzers: Determination of allowable interference limits according to different calculation methods

<div><p></p><p><b><i>Objectives.</i></b> To determine the hemolysis interference on biochemical tests and immunoassays performed on Roche Diagnostics analyzers, according to different maximum allowable limits. <b><i>Design and methods.</i></b> Heparinized plasma and serum pools, free of interferences, were overloaded by increasing amounts of a hemoglobin-titrated hemolysate. This interference was evaluated for 45 analytes using Modular^® and Cobas^® analyzers. For each parameter, the hemolysis index (HI) corresponding to the traditional ± 10% change of concentrations from baseline (± 10%Δ) was determined, as well as those corresponding to the analytical change limit (ACL), and to the reference change value (RCV). Then, the relative frequencies distribution (% RFD) of hemolyzed tests performed in a hospital laboratory over a 25-day period were established for each HI as allowable limit. <b><i>Results.</i></b> Considering the ± 10%Δ, the analyte concentrations enhanced by hemolysis were: Lactate dehydrogenase (LDH), aspartate aminotransferase (AST), folate, potassium, creatine kinase, phosphorus, iron, alanine aminotransferase, lipase, magnesium and triglycerides, decreasingly. The analyte concentrations decreased by hemolysis were: Haptoglobin, high-sensitive troponin T and alkaline phosphatase. Over the 25-day period, the % RFD of tests impacted more than 10%Δ by hemolysis were < 7% for LDH; < 5% for AST, folates and iron; and < 1% for the other analytes. Considering the ACL, HI were lower, giving % RFD substantially increased for many analytes, whereas only four analytes remain sensitive to hemolysis when considering RCV. <b><i>Conclusion.</i></b> This study proposes new HI based on different allowable limits, and can therefore serve as a starting point for future harmonization of hemolysis interference evaluation needed in routine laboratory practice.</p></div

Clinical data of probands and relatives carrying a large <i>PKP2</i> heterozygous deletion.

<p>Clinical data of probands and relatives carrying a large <i>PKP2</i> heterozygous deletion.</p

Detailed list and characteristics of putative mutations.

<p>Detailed list and characteristics of putative mutations.</p

Schematic view of <i>PKP2</i> deletions.

<p>Schematic view of <i>PKP2</i> deletions.</p

Representative immunolocalization of intercalated disc proteins in ARVD/C patient right ventricles.

<p>Representative pictures of plakophilin-2, β-catenin, plakoglobin, desmoglein-2 and desmocollin-2 labeling are shown (in green). Cardiac myosin-binding protein C (cMyBP-C) and α-actinin-2 (both red labeling) were used as cardiomyocyte specific markers. The figure shows heart tissue from two patients with ARVD/C compared to a representative (non ARVD/C) control.</p

Quantitative immunoblotting of selected intercalated disk proteins; plakophilin-2, plakoglobin and β-catenin.

<p>Representative immunoblots obtained for (a) plakoglobin (left Ventricle), (b) β-catenin (septum) and (c) plakophilin-2 (septum). Bar graphs indicate the mean ± SEM following quantification of protein signals from all blots from the seven patient tissue samples and all compartments after normalization to the cardiac protein α-actinin-2 (ACTN2) or cardiac myosin-binding protein C (cMyBP-C) and to the control with the strongest signal level. NS for <i>p</i>>0.05, Mann Whitney test.</p