Clinical Characteristics and Follow-Up of Pediatric-Onset Arrhythmogenic Right Ventricular Cardiomyopathy.

OBJECTIVES: The goal of this study was to describe characteristics, cascade screening results, and predictors of adverse outcome in pediatric-onset arrhythmogenic right ventricular cardiomyopathy (ARVC). BACKGROUND: Although ARVC is increasingly recognized in children, pediatric ARVC cohorts remain underrepresented in the literature. METHODS: This study included 12 probands with pediatric-onset ARVC (aged <18 years at diagnosis) and 68 pediatric relatives (aged <18 years at first evaluation) referred for cascade screening. ARVC diagnosis was based on 2010 Task Force Criteria. Clinical presentation, diagnostic testing, and outcomes (sustained ventricular tachycardia [VT]; heart failure) were ascertained. Predictors of adverse outcome were determined by using univariable logistic regression. RESULTS: Pediatric-onset ARVC was diagnosed in 12 probands and 12 (18%) relatives at a median age of 16.6 years (interquartile range: 13.8-17.4 years), whereas 12 (18%) relatives reached ARVC diagnosis as adults (median age, 22.0 years; interquartile range: 20.0-26.7 years). Sudden cardiac death/arrest was the first disease manifestation in 3 (25%) probands and 3 (4%) relatives. In patients without ARVC diagnosis at presentation (n = 61), electrocardiogram and Holter monitoring abnormalities occurred before development of imaging Task Force Criteria (7.3 ± 5.0 years vs 8.4 ± 5.0 years). Clinical course was characterized by sustained VT (91%) and heart failure (36%) in probands, which were rare in relatives (2% and 0%, respectively). Male sex (P < 0.01), T-wave inversion V1-V3 (P < 0.01), premature ventricular complexes/runs (P ≤ 0.01), and decrease in biventricular ejection fraction (P ≤ 0.01) were associated with VT occurrence. CONCLUSIONS: Pediatric ARVC carries high arrhythmic risk, especially in probands. Disease progression is particularly observed on electrocardiogram or Holter monitoring. Arrhythmic events are associated with male sex, T-wave inversions, premature ventricular complexes/runs, and reduced biventricular ejection fraction.

Exercise capacity in patients with repaired Tetralogy of Fallot aged 6 to 63 years.

OBJECTIVES: This study aimed to provide a perspective for the interpretation of exercise capacity (peakVO2) in patients with repaired Tetralogy of Fallot (patients with rTOF) by describing the course of peakVO2 from patients aged 6-63 years. METHODS: A retrospective study was performed between September 2001 and December 2016 in the German Heart Centre Munich, Germany, and in the University Medical Centre Groningen, the Netherlands. A total of 1175 cardiopulmonary exercise tests (CPETs) were collected from 586 patients with rTOF, 46% female. Maximal exertion was verified using a respiratory exchange ratio ≥1.00. PeakVO2 was modelled using time-dependent multilevel models for repeated measurements (n=889 in 300 patients), and compared with subject-specific reference values calculated by the models of Bongers et al and Mylius et al. RESULTS: The peakVO2 of patients with rTOF was reduced at all ages. At the age of 6, the peakVO2 was 614 mL/min (70% of predicted (95% CI 67 to 73)). The reduced increase in peakVO2 during adolescence resulted in a significant lower maximum peakVO2 of 1209 mL/min at 25 years (65% predicted, p<0.001). A linear decline after 25 years was observed in patients and references, although patients showed an accelerated decline, with a -0.24% point of predicted (95% CI 0.11 to 0.38) per year without differences between sexes (p=0.263). CONCLUSIONS: This study provides a context for peakVO2 across ages in patients with rTOF under contemporary treatment strategies. It showed that the reduction in peakVO2 originates from childhood and declines over time. Sex differences in patients with rTOF were similar to natural existing sex differences.

Autologous Right Auricular Versus PTFE Cavopulmonary Lateral Tunnel: Influence of Surgical Technique on Arrhythmias.

BACKGROUND: To compare the incidence of arrhythmias and the overall survival at long-term follow-up of the right auricular baffle technique (RA) versus Gore-Tex® (GT) baffle as intra-atrial cavopulmonary lateral tunnel, as well as the Nakata index and tunnel dimensions on cardiac magnetic resonance. METHODS: Data were retrospectively collected. Serial 24-hour Holter recordings and cardiac magnetic resonance findings of the two groups were compared. RESULTS: There was no significant difference in the estimated freedom from arrhythmias (87% at 10 years and 78% at 15 years vs 80% at 10 years and 70% at 15 years in RA and GT, respectively; P = .44) nor cumulative survival (86% at 10 years and 84% at 15 years vs 97% at 10 years and 81% at 15 years in RA and GT, respectively; P = .8). Also, no difference between the groups was observed in the Nakata index. The tunnel dimensions on cardiac magnetic resonance were significantly wider in the RA group. In reference to other potential risk indicators, using Cox proportional hazard regression analysis, only age (5 years or older at the time of total cavopulmonary connection) was associated with an increased risk for both arrhythmia and mortality. CONCLUSIONS: This study demonstrated that there was no difference in freedom from arrhythmias, Nakata index, or survival between the two groups. This study confirmed the growth potential of the right auricular tunnel. However, the growth of the tunnel did not influence the incidence of arrhythmias.

Linking the heart and the brain: Neurodevelopmental disorders in patients with catecholaminergic polymorphic ventricular tachycardia.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an uncommon inherited arrhythmia disorder characterized by adrenergically evoked ventricular arrhythmias. Mutations in the cardiac calcium release channel/ryanodine receptor gene (RYR2) are identified in the majority of patients with CPVT. RyR2 is also the major RyR isoform expressed in the brain. OBJECTIVE: The purpose of this study was to estimate the prevalence of intellectual disability (ID) and other neurodevelopmental disorders (NDDs) in RYR2-associated CPVT (CPVT1) and to study the characteristics of these patients. METHODS: We reviewed the medical records of all CPVT1 patients from 12 international centers and analyzed the characteristics of all CPVT1 patients with concomitant NDDs. We functionally characterized the mutations to assess their response to caffeine activation. We did not correct for potential confounders. RESULTS: Among 421 CPVT1 patients, we identified 34 patients with ID (8%; 95% confidence interval 6%-11%). Median age at diagnosis was 9.3 years (interquartile range 7.0-14.5). Parents for 24 of 34 patients were available for genetic testing, and 13 of 24 (54%) had a de novo mutation. Severity of ID ranged from mild to severe and was accompanied by other NDDs in 9 patients (26%). Functionally, the ID-associated mutations showed a markedly enhanced response of RyR2 to activation by caffeine. Seventeen patients (50%) also had supraventricular arrhythmias. During median follow-up of 8.4 years (interquartile range 1.8-12.4), 15 patients (45%) experienced an arrhythmic event despite adequate therapy. CONCLUSION: Our study indicates that ID is more prevalent among CPVT1 patients (8%) than in the general population (1%-3%). This subgroup of CPVT1 patients reveals a malignant cardiac phenotype with marked supraventricular and ventricular arrhythmias.

Strong population structure but no equilibrium yet: Genetic connectivity and phylogeography in the kelp Saccharina latissima (Laminariales, Phaeophyta).

Kelp aquaculture is globally developing steadily as human food source, along with other applications. One of the newer crop species is Saccharina latissima, a northern hemisphere kelp inhabiting temperate to arctic rocky shores. To protect and document its natural genetic variation at the onset of this novel aquaculture, as well as increase knowledge on its taxonomy and phylogeography, we collected new genetic data, both nuclear and mitochondrial, and combined it with previous knowledge to estimate genetic connectivity and infer colonization history. Isolation-with-migration coalescent analyses demonstrate that gene flow among the sampled locations is virtually nonexistent. An updated scenario for the origin and colonization history of S. latissima is developed as follows: We propose that the species (or species complex) originated in the northwest Pacific, crossed to the northeast Pacific in the Miocene, and then crossed the Bering Strait after its opening ~5.5 Ma into the Arctic and northeast Atlantic. It subsequently crossed the Atlantic from east to west. During the Pleistocene, it was compressed in the south with evidence for northern refugia in Europe. Postglacial recolonization led to secondary contact in the Canadian Arctic. Saccharina cichorioides is shown to probably belong to the S. latissima species complex and to derive from ancestral populations in the Asian North Pacific. Our novel approach of comparing inferred gene flow based on coalescent analysis versus Wright's island model suggests that equilibrium levels of differentiation have not yet been reached in Europe and, hence, that genetic differentiation is expected to increase further if populations are left undisturbed.

Physical Activity in Pediatric Pulmonary Arterial Hypertension Measured by Accelerometry. A Candidate Clinical Endpoint.

RATIONALE: The development of evidence-based treatment guidelines for pediatric pulmonary arterial hypertension (PAH) is hampered by lack of pediatric clinical trials. Trial design is hampered by lack of a feasible clinical endpoint in this population. OBJECTIVES: To evaluate the use of accelerometry for measuring physical activity (PA) in pediatric PAH and to investigate its correlation with clinical disease severity markers. METHODS: We included children from the Dutch National Network for Pediatric Pulmonary Hypertension. Control patients were recruited from the outpatient cardiology clinic of the Beatrix Children's Hospital. Children were asked to wear the accelerometer for 7 days. Vector magnitude counts per minute (VM CPM) and time per day spent in different PA intensity levels were defined as accelerometer outcomes. MEASUREMENTS AND MAIN RESULTS: VM CPM was lower in children with PAH (n = 29) than in controls (n = 60; 647 vs. 921; P < 0.001). Children with PAH spent less time in moderate and vigorous PA (13 vs. 29 min/d and 2 vs. 13 min/d, respectively; P < 0.001). Time spent in moderate and vigorous PA correlated inversely with World Health Organization functional class. Time spent in moderate PA correlated positively with 6-minute-walk distance. In post hoc analyses, VM CPM and time spent in moderate/vigorous combined and vigorous PA were associated with outcome (P ≤ 0.044). CONCLUSIONS: PA is markedly decreased in children with PAH. Accelerometer output correlated with clinical disease severity markers and may predict outcome. We showed an exciting potential of PA as a meaningful endpoint for clinical trials in pediatric PAH, although its clinical utility and prognostic value need to be further validated.

Exploration of the phycoremediation potential of Laminaria digitata towards diflubenzuron, lindane, copper and cadmium in a multitrophic pilot-scale experiment.

The presence of contaminants in aquatic ecosystems can cause serious problems to the environment and marine organisms. This study aims to evaluate the phycoremediation capacity of macroalgae Laminaria digitata for pesticides (diflubenzuron and lindane) and toxic elements (cadmium and copper) in seawater in the presence or absence of mussels. The photosynthetic activity was monitored in the macroalgae to assess its "physiological status". The results showed that the presence of algae decreased diflubenzuron concentration in mussels by 70% after 120 h of exposure. Additionally, this macroalgae was efficient to reduce lindane, Cu and Cd in seawater; even though it not was able to reduce these contaminants in mussels. The studied pollutants did not affect the physiological status of macroalgae. This study reveals that the application of phycoremediation with macroalgae can be an useful and effective mitigation strategy to remove/decrease contaminant levels from the aquatic environment.

Vein of Galen Aneurysmal Malformation in Neonates Presenting With Congestive Heart Failure.

The authors report the case of a neonate presenting with signs of a congenital cardiac disease. Echocardiography showed a structural normal heart, right-to-left ductal flow, a dilated superior caval vein, and reversed diastolic flow in the proximal descending aorta. Brain magnetic resonance imaging showed a vein of Galen arteriovenous malformation. This highlights the importance of considering an intracranial cause in the differential diagnosis of neonatal congestive heart failure.

Off-pump hepatic to azygos connection via thoracotomy for relief of fistulas after a Kawashima procedure: Ten-year results.

OBJECTIVES: An almost universal incidence of developing pulmonary arteriovenous fistulas after the Kawashima operation has been reported. Exclusion of the hepatic venous flow from the pulmonary circulation causes the development of these malformations. Redirection of hepatic venous flow to the pulmonary circulation mostly leads to the regression of the arteriovenous fistulas. METHODS: We analyzed 11 patients with arteriovenous fistulas that developed after the Kawashima operation. The hepatic-to-azygos shunts were performed with an off-pump technique through a lateral thoracotomy in all but one. Operative and postoperative data were retrospectively collected. RESULTS: No intraoperative complications occurred, and no patient died in the hospital. Up to 10-year follow-up showed a significant postoperative improvement of patients' oxygen saturation and New York Heart Association class. Apart from 2 re-thoracotomies for bleeding in 1 patient, no complications occurred and no patient died during follow-up. Two other patients underwent reoperation for an undiagnosed additional hepatic vein. The improvement of patients' oxygen saturation and New York Heart Association class persisted during the follow-up period. CONCLUSIONS: The surgical connection can be performed safely with an off-pump technique that avoids the risks related to extracorporeal circulation and circulatory arrest. The results at 10 years follow-up confirmed the efficacy and safety of the surgical technique described.

Lusoria flap for the management of aortic coarctation in an eight-year-old child.

Anomalous origin of right subclavian artery arising from the descending aorta is known as "arteria lusoria." The diagnosis in asymptomatic children is usually the by-product of other symptomatic-associated anomalies, such as aortic coarctation. We describe a case of an eight-year-old boy with juxtaductal aortic coarctation and rare origin of the arteria lusoria proximal to the aortic coarctation. The anomalous arteria lusoria was used as a flap to repair the aortic coarctation. To the authors' knowledge, this is the first reported application of lusoria flap in a young child (not newborn) with ductal aortic coarctation.

Not all beta-blockers are equal in the management of long QT syndrome types 1 and 2: higher recurrence of events under metoprolol.

OBJECTIVES: The purpose of this study was to compare the efficacy of beta-blockers in congenital long QT syndrome (LQTS). BACKGROUND: Beta-blockers are the mainstay in managing LQTS. Studies comparing the efficacy of commonly used beta-blockers are lacking, and clinicians generally assume they are equally effective. METHODS: Electrocardiographic and clinical parameters of 382 LQT1/LQT2 patients initiated on propranolol (n = 134), metoprolol (n = 147), and nadolol (n = 101) were analyzed, excluding patients <1 year of age at beta-blocker initiation. Symptoms before therapy and the first breakthrough cardiac events (BCEs) were documented. RESULTS: Patients (56% female, 27% symptomatic, heart rate 76 ± 16 beats/min, QTc 472 ± 46 ms) were started on beta-blocker therapy at a median age of 14 years (interquartile range: 8 to 32 years). The QTc shortening with propranolol was significantly greater than with other beta-blockers in the total cohort and in the subset with QTc >480 ms. None of the asymptomatic patients had BCEs. Among symptomatic patients (n = 101), 15 had BCEs (all syncopes). The QTc shortening was significantly less pronounced among patients with BCEs. There was a greater risk of BCEs for symptomatic patients initiated on metoprolol compared to users of the other 2 beta-blockers combined, after adjustment for genotype (odds ratio: 3.95, 95% confidence interval: 1.2 to 13.1, p = 0.025). Kaplan-Meier analysis showed a significantly lower event-free survival for symptomatic patients receiving metoprolol compared to propranolol/nadolol. CONCLUSIONS: Propranolol has a significantly better QTc shortening effect compared to metoprolol and nadolol, especially in patients with prolonged QTc. Propranolol and nadolol are equally effective, whereas symptomatic patients started on metoprolol are at a significantly higher risk for BCEs. Metoprolol should not be used for symptomatic LQT1 and LQT2 patients.

Familial evaluation in catecholaminergic polymorphic ventricular tachycardia: disease penetrance and expression in cardiac ryanodine receptor mutation-carrying relatives.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome associated with mutations in the cardiac ryanodine receptor gene (Ryr2) in the majority of patients. Previous studies of CPVT patients mainly involved probands, so current insight into disease penetrance, expression, genotype-phenotype correlations, and arrhythmic event rates in relatives carrying the Ryr2 mutation is limited. METHODS AND RESULTS: One-hundred sixteen relatives carrying the Ryr2 mutation from 15 families who were identified by cascade screening of the Ryr2 mutation causing CPVT in the proband were clinically characterized, including 61 relatives from 1 family. Fifty-four of 108 antiarrhythmic drug-free relatives (50%) had a CPVT phenotype at the first cardiological examination, including 27 (25%) with nonsustained ventricular tachycardia. Relatives carrying a Ryr2 mutation in the C-terminal channel-forming domain showed an increased odds of nonsustained ventricular tachycardia (odds ratio, 4.1; 95% CI, 1.5-11.5; P=0.007, compared with N-terminal domain) compared with N-terminal domain. Sinus bradycardia was observed in 19% of relatives, whereas other supraventricular dysrhythmias were present in 16%. Ninety-eight (most actively treated) relatives (84%) were followed up for a median of 4.7 years (range, 0.3-19.0 years). During follow-up, 2 asymptomatic relatives experienced exercise-induced syncope. One relative was not being treated, whereas the other was noncompliant. None of the 116 relatives died of CPVT during a 6.7-year follow-up (range, 1.4-20.9 years). CONCLUSIONS: Relatives carrying an Ryr2 mutation show a marked phenotypic diversity. The vast majority do not have signs of supraventricular disease manifestations. Mutation location may be associated with severity of the phenotype. The arrhythmic event rate during follow-up was low.

Severe cardiac phenotype with right ventricular predominance in a large cohort of patients with a single missense mutation in the DES gene.

BACKGROUND: Desmin-related myopathy is a clinically heterogenous group of disorders encompassing myopathies, cardiomyopathies, conduction disease, and combinations of these disorders. Mutations in the gene encoding desmin (DES), a major intermediate filament protein, can underlie this phenotype. OBJECTIVE: The purpose of this study was to investigate the clinical and pathologic characteristics of 27 patients from five families with an identical mutation in the head domain region (p.S13F) of desmin. METHODS/RESULTS: All 27 carriers or obligate carriers of a p.S13F DES founder mutation demonstrated a fully penetrant yet variable phenotype. All patients demonstrated cardiac involvement characterized by high-grade AV block at young ages and important right ventricular (RV) involvement. RV predominance was demonstrated by the presence of right bundle branch block in 10 patients (sometimes as a first manifestation) and by RV heart failure in 6 patients, including 2 patients who fulfilled the diagnostic criteria for arrhythmogenic RV cardiomyopathy. Because of this clinical overlap with desmosome cardiomyopathies, we also studied the organization of the intercalated disks, particularly the distribution of desmosomal proteins. Normal amounts of the major desmosomal proteins were found, but the intercalated disks were more convoluted and elongated and had a zigzag appearance. CONCLUSION: In this largest series to date of individuals with a single head domain DES mutation, patients show a variable yet predominantly cardiologic phenotype characterized by conduction disease at an early age and RV involvement including right bundle branch block and/or RV tachycardias and arrhythmogenic RV cardiomyopathy phenocopies. A localized effect of desmin on the structure of the cardiac intercalated disks might contribute to disease pathogenesis.

Off-pump connection of the hepatic to the azygos vein through a lateral thoracotomy for relief of arterio-venous fistulas after a Kawashima procedure.

OBJECTIVE: To connect the hepatic veins to the azygos venous system through a lateral thoracotomy, and without the use of extracorporeal circulation, so as to relieve arteriovenous fistulas after a previous Kawashima operation. METHODS: Description of the operative technique by which the hepatic veins are anastomosed to the hepatic venous system. RESULTS: The surgical approach was successfully applied in 3 patients, all of whom showed an excellent rise of saturations of oxygen after redirection of the hepatic venous blood. CONCLUSION: The operative method presented is an elegant means of redirecting the hepatic venous blood to the pulmonary circulation without the disadvantages of extracorporeal circulation and resternotomy.

Drug management of fetal tachyarrhythmias: are we ready for a systematic and evidence-based approach?

Fetal tachyarrhythmias are a life-threatening condition complicating a small proportion of normal pregnancies. Despite major advances in the (intrauterine) pharmacologic treatment of these arrhythmias over the last years major uncertainties remain. Among these are controversies in the choice of agents in relation to arrhythmia type, and timing and duration of treatment. Currently, no evidence-based approach to the management of fetal tachyarrhythmias is available. An international registry is proposed as an important step toward obtaining the necessary data to develop evidence-based management strategies.