Congenital Long QT Syndrome in Children and Adolescents: A General Overview.

Congenital long QT syndrome (LQTS) represents a disorder of myocardial repolarization characterized by a prolongation of QTc interval on ECG, which can degenerate into fast polymorphic ventricular arrhythmias. The typical symptoms of LQTS are syncope and palpitations, mainly triggered by adrenergic stimuli, but it can also manifest with cardiac arrest. At least 17 genotypes have been associated with LQTS, with a specific genotype-phenotype relationship described for the three most common subtypes (LQTS1, -2, and -3). ß-Blockers are the first-line therapy for LQTS, even if the choice of the appropriate patients needing to be treated may be challenging. In specific cases, interventional measures, such as an implantable cardioverter-defibrillator (ICD) or left cardiac sympathetic denervation (LCSD), are useful. The aim of this review is to highlight the current state-of-the-art knowledge on LQTS, providing an updated picture of possible diagnostic algorithms and therapeutic management.

Brugada Syndrome: Focus for the General Pediatrician.

Brugada Syndrome is an "inherited" channelopathy characterized by a predisposition to syncope and sudden death. It typically presents in young adults but is also known to affect the pediatric population, even if the prevalence is low compared to the adult population. The diagnostic ECG pattern shows coved-type ST-segment elevation in the right precordial leads, occurring spontaneously or after provocative drug tests with IV administration of Class I antiarrhythmic drugs. However, the electrocardiographic findings may vary, and transient or concealed forms of the syndrome further complicate diagnosis, necessitating thorough evaluation and close clinical follow-up. The clinical presentation of Brugada Syndrome may range from asymptomatic individuals to patients who have experienced syncope or sudden cardiac arrest. The syndrome remains underdiagnosed due to its elusive symptoms and the absence of abnormal findings between episodes. Additionally, specific triggers such as fever, certain medications and alcohol consumption may unmask the electrocardiographic changes and provoke arrhythmias in susceptible individuals. Given its elusive nature, early diagnosis and risk stratification are crucial in identifying individuals who may benefit from an implantable cardioverter defibrillator, the mainstay of treatment for high-risk patients, or pharmacological interventions.

A new family with a case of severe early-onset muscle fatigue and a peculiar maternally inherited painful swelling in chewing muscles associated with homoplasmic m.15992A>T mutation in mitochondrial tRNAPro.

A 16-year-old boy was evaluated for a history of exercise-induced fatigability associated with nausea even after minimal effort, lower limbs muscle hypotrophy, and swelling of the masseter muscles after chewing. Laboratory tests were remarkable for hyperlactatemia and metabolic acidosis after short physical activity. The muscle biopsy showed non-specific mitochondrial alterations and an increase in intrafibral lipids. Biochemical analysis showed reduced activity of the respiratory chain complexes. Mitochondrial DNA sequencing revealed the presence of a homoplasmic variant m.15992A>T in the MT-TP gene, coding for the mt-tRNAPro in the patient, in his mother and in his brother. Pathogenic or likely pathogenic variants in MT-TP gene are rare. They are responsible for different clinical presentation, almost ever involving the muscle tissue. We report the first family with exercise-induced muscle weakness and swelling of the chewing muscles due to m.15992A>T variant in absence of J1c10 haplogroup, confirming its pathogenicity.

Characterization of Cardiac Function by Echocardiographic Global Longitudinal Strain in a Cohort of Children with Neurofibromatosis Type 1 Treated with Selumetinib.

BACKGROUND: Plexiform neurofibromas are benign neoplasms that develop in 20-50% children with neurofibromatosis type 1 (NF1). Selumetinib was approved as treatment for symptomatic and inoperable plexiform neurofibromas. Subclinical left ventricular ejection fraction reduction is a less common effect of selumetinib. OBJECTIVE: We aimed to investigate the contractile function of the heart in a cohort of children with NF1 treated with selumetinib. METHODS: We designed a cross-sectional study including 17 patients with NF1 who received selumetinib. Echocardiographic parameters were compared with a cohort of 17 healthy children matched by sex and age and another group of 17 children with untreated NF1. RESULTS: Compared with healthy controls, patients with NF1 treated with selumetinib had lower mean values of global longitudinal strain (- 22.9 ± 2% vs -25.5 ± 2%; p = 0.001), fractional shortening (36 ± 4% vs 43 ± 8%; p = 0.02) and tricuspid annular plane systolic excursion (19 ± 3 mm vs 23 ± 2 mm; p = 0.001); no difference was found in left ventricular ejection fraction (63 ± 4% vs 65 ± 3%; p = 0.2 respectively). Median treatment time with selumetinib at the time of the echocardiographic evaluation was 22 ± 16 months. CONCLUSIONS: Patients with NF1 treated with selumetinib may experience subtle changes in systolic function identified by global longitudinal strain and not revealed by left ventricular ejection fraction. Global longitudinal strain might be useful to monitor cardiac function in this cohort of patients for the duration of therapy.

New insights on Noonan syndrome's clinical phenotype: a single center retrospective study.

BACKGROUND: Noonan syndrome (NS) is a clinically and genetically heterogeneous disorder. Since its clinical phenotype is often mild and difficult to differentiate from other syndromes, its diagnosis can be challenging and its prevalence in the pediatric population is most certainly underestimated. The difficulty in identifying Noonan syndrome is also increased by the fact that genetic tests are currently not able to detect an underlying mutation in around 10% of the cases. METHODS: This is a retrospective, observational study conducted at the Institute for Maternal and Child "Burlo Garofolo" in Trieste, Italy. We recruited all the patients with clinical and/or genetic diagnosis of NS who were evaluated at the Department of Pediatrics between October 2015 and October 2020. Statistical analyses were performed with IBM SPSS Statistics software. The association between discrete variables has been evaluated through chi-squared test, indicating statistically significant p with Pearson test or Fischer test for variables less than 5. RESULTS: We recruited a total of 35 patients affected by Noonan syndrome. In 24 patients (75%) we identified an underlying genetic substrate: 17 patients had a mutation on PTPN11 (61%), 2 in SOS1, KRAS and SHOC2 (7% each) and only 1 in RAF1 (4%). 25% of the subjects did not receive a genetic confirm. As for the phenotype of the syndrome, our study identified the presence of some clinical features which were previously unrelated or poorly related to NS. For example, renal and central nervous system abnormalities were found at a higher rate compared to the current literature. On the contrary, some features that are considered very suggestive of NS (such as lymphatic abnormalities and the classical facial features) were not frequently found in our population. CONCLUSIONS: In our analysis, we focused on the main phenotypic features of NS, identifying various clinical manifestation that were not associated with this genetic condition before. This could be helpful in raising the knowledge of NS's clinical spectrum, facilitating its diagnosis.

Long QT syndrome and left ventricular non-compaction in a family with KCNH2 mutation: A case report.

Background: Left ventricular non-compaction (LVNC) is an abnormality of the myocardium, characterized by prominent left ventricular trabeculae and deep inter-trabecular recesses. Long QT syndrome (LQTS) is a cardiac ion channelopathy presenting with a prolonged QT interval on resting electrocardiogram and is associated with increased susceptibility to sudden death. The association between LVNC and LQTS is uncommon. Case presentation: We report an Italian family with a novel pathogenic KCNH2 variant who presented with clinical features of LVNC and LQTS. The proband came to our attention after two syncopal episodes without prodromal symptoms. His ECG showed QTc prolongation and deep T wave inversion in anterior leads, and the echocardiogram fulfilled LVNC criteria. After that, also his sister was found to have LQTS and LVNC, while his father only presented LQTS. Conclusions: Physicians should be aware of the possible association between LVNC and LQTS. Even if this association is rare, patients with LVNC should be investigated for LQTS to prevent possible severe or even life-threatening arrhythmic episodes.

Cardio-pulmonary function among children with mild or asymptomatic COVID-19 infection needing certification for return-to-play.

AIM: To explore the cardio-pulmonary function of children returning to play sports after mild or asymptomatic SARS-CoV-2 infection. METHODS: This is a consecutive case series conducted at the Institute for Maternal and Child Health, Trieste, Italy. Paediatric patients who accessed the Institute for cardiologic and pneumological evaluation before the return-to-play competitive sports were recruited, according to the Italian Sports Medical Federation recommendations. Echocardiogram, electrocardiogram, treadmill ECG test and pulmonary function tests were performed. RESULTS: One hundred and thirty-two patients (aged 8-17 years old, mean age 12.8 ± 2.5) were recruited. Among these, 127 children were considered for the final analysis (49.6% females). Out of 127, 84 (66.1%) had a mild symptomatic form of SARS-CoV-2 infection, while 43 (33.9%) were asymptomatic. The main referred symptoms were fever (n = 37, 44%), asthenia (n = 14, 16.7%), rhinitis (n = 16, 19%), ageusia (n = 19, 22.6%), anosmia (n = 24, 28.6%), sore throat (n = 3, 3.6%), cough (n = 9, 10.7%), arthralgia-myalgia (n = 11, 13.1%), headache (n = 23, 27.4%) and gastrointestinal symptoms (n = 7, 8.3%). No child presented evidence of cardio-pulmonary function impairment after an average time of 77.3 days (SD 35) from SARS-CoV-2 swab positivity and a median of 68 days (IQ1 52, IQ3 92.5). CONCLUSION: This preliminary study suggests that, in the absence of specific symptoms, the diagnostic yield of cardio-pulmonary tests before returning to play sports may be very low.

Anomalous aortic origin of coronary artery: For a challenging diagnosis, a transthoracic echocardiogram is recommended.

Anomalous aortic origin of a coronary artery (AAOCA), especially the interarterial course of the right or left coronary artery, predisposes paediatric patients to myocardial ischaemia. This rare condition is a leading cause of sudden cardiac death. General paediatricians face challenges when diagnosing this anomaly, and they should pay particular attention to the recurrence of exercise-related syncope without prodromal symptoms, chest pain and dyspnoea. An accurate transthoracic echocardiogram with Doppler colour flow mapping is the best method to use to identify AAOCA. CONCLUSION: Identifying an AAOCA is challenging, and we provide advice on clinical red flags and diagnostic approaches for general paediatricians.

Cardiomyopathies in children: classification, diagnosis and treatment.

PURPOSE OF REVIEW: Cardiomyopathies are rare in the pediatric population, but significantly impact on morbidity and mortality. The present review aims to provide an overview of cardiomyopathies in children and some practical guidelines for their prognostic stratification and management. RECENT FINDINGS: Pediatric cardiomyopathies may present as isolated cardiac muscle disease or in the context of complex clinical syndromes. The etiologic characterization represents an important step in the diagnosis and treatment of cardiomyopathies because of its impact on prognosis and on therapeutic measures. Indeed, replacement therapy is nowadays widely available and changes the natural history of the disease. More complex is the management of isolated cardiomyopathies, which lack specific therapies, mainly aimed at symptomatic relief. In this context, heart transplantation shows excellent outcomes in children, but wait-list mortality is still very high. Device therapy for sudden cardiac death prevention and the use of mechanical assist devices are becoming more common in the clinical practice and may help to reduce mortality. SUMMARY: Providing insight into pediatric cardiomyopathies classification helps in the prognostication and management of such diseases. Recent years witnessed a significant improvement in mortality, but future research is still needed to improve quality of life and life expectations in the pediatric population.

Retrospective study showed that palpitations with tachycardia on admission to a paediatric emergency department were related to cardiac arrhythmias.

AIM: This retrospective study reviewed the prevalence and long-term prognosis of children aged 0-18 with palpitations who were admitted to the emergency department (ED) of an Italian paediatric hospital. METHODS: We examined all admissions to the ED of the IRCCS Burlo Garofolo between January 2009 and December 2015 by selecting triage diagnoses of palpitations. The hospital discharge cards were reviewed to assess vital parameters, physical examinations, diagnostic tests, cardiology consultations and final diagnoses. RESULTS: Of the 142 803 patients who attended our ED for any reason, 96 (0.07%) complained of palpitations. Despite this low prevalence, it was noteworthy that 13.5% had a real underlying arrhythmic cause and needed medical assistance. Over half (52.1%) were women and the mean age was 12.7 years. At the long-term follow-up, at a mean of 47 ± 23 months, 53.8% of patients with a cardiac arrhythmia had received medical therapy and 46.1% had undergone trans-catheter ablation for supraventricular tachycardia. A heart rate above 146 beats per minute or palpitations for more than an hour was statistically related to a cardiac arrhythmia. CONCLUSION: Palpitations were an infrequent cause of admission to our ED, but 13.5% who displayed them had an underlying cardiac arrhythmia.

Comparison of Patient Characteristics and Course of Hypertensive Hypokinetic Cardiomyopathy Versus Idiopathic Dilated Cardiomyopathy.

Hypertensive hypokinetic cardiomyopathy (HHC) is defined by left ventricular (LV) systolic dysfunction with a history of systemic hypertension as the only possible cause. Although commonly encountered in clinical practice, its characterization and differences with true idiopathic dilated cardiomyopathy (IDC) are lacking. The aim of this study was to characterize the clinical instrumental features and the natural history of HHC. We analyzed the data of 4,191 patients referred to our center for newly diagnosed LV systolic dysfunction from 2005 to 2010. Of them, 310 presented idiopathic LV systolic dysfunction (LV ejection fraction <50%): 136 (44%) had a history of systemic hypertension and were defined HHC. The remaining 174 patients were considered IDC. Compared with patients with IDC, those with HHC were older (63 ± 11 vs 47 ± 14 years, p <0.001), with worse comorbidity profile, higher blood pressure, and increased LV mass. During follow-up, patients with HHC showed earlier and higher proportion of LV reverse remodeling (46% vs 21% at 6 months' follow-up). Moreover, they had a better long-term survival free from cardiovascular death/ventricular assist device/heart transplant/malignant ventricular arrhythmias (5.1 vs 12.6 in HHC and IDC, p = 0.03). Indeed, their mortality was mainly driven by noncardiovascular causes (at 10 years 9.6% vs 1.7% in HHC and IDC, p <0.001). In conclusion, HHC has a high prevalence among patients with "idiopathic" LV dysfunction. The natural history of patients with HHC is characterized by a rapid response to optimal therapy for heart failure, a favorable cardiovascular outcome, and a relevant incidence of noncardiovascular events.

Cardiac involvement in patients with rheumatic disorders: Data of the RHEU-M(A)R study.

BACKGROUND: The diagnosis of cardiac involvement in rheumatic disorders is challenging due to its varying clinical presentation. Since clinical consequences range from immediate treatment changes to adverse long-term outcome, individual risk stratification is of great clinical interest. Primary aim was to evaluate the prevalence of cardiac involvement in patients with different rheumatic disorders using late gadolinium enhancement-cardiac magnetic resonance imaging (LGE-CMR). In addition, we sought to investigate if different rheumatic disorders would demonstrate different LGE patterns. METHODS: Two-hundred-ninety-seven patients with rheumatic disorders were included and underwent LGE-CMR for work-up of cardiac involvement, which was defined by the presence of LGE in the myocardium. Patients were divided into five subgroups: 1) ANCA-associated vasculitis, 2) non-ANCA-associated vasculitis, 3) connective tissue disorders, 4) arthritis, and 5) sarcoidosis. RESULTS: Mean ejection fraction in the overall population was 65%, with a mean age of 55yrs. Prevalence of cardiac involvement in the five subgroups were as follows: 54% in the ANCA-associated vasculitis group, 22% in the non-ANCA-associated vasculitis group, 14% in the group with connective tissue disorders, 21% in the arthritis group, and 24% in sarcoid patients. Each of the five subgroups demonstrated a distinct pattern of LGE. CONCLUSION: There is a wide range in the prevalence of cardiac involvement in different rheumatic disorders (54%-14%). Different groups of rheumatic disorders demonstrate different patterns of LGE. CONDENSED ABSTRACT: Primary aim of the study was to evaluate the presence of cardiac involvement in patients with different rheumatic disorders using LGE-CMR. In addition, we sought to investigate if different rheumatic disorders would reveal different LGE patterns. In our 297 patients, the highest prevalence of cardiac involvement was found in patients with ANCA-associated vasculitis (54%), whereas the lowest prevalence was demonstrated in patients with connective tissue disorders (14%). Furthermore, different groups of rheumatic disorders demonstrate distinct patterns of LGE.

Insight into genetic determinants of resting heart rate.

BACKGROUND: Recent studies suggested that resting heart rate (RHR) might be an independent predictor of cardiovascular mortality and morbidity. Nonetheless, the interrelation between RHR and cardiovascular diseases is not clear. In order to resolve this puzzle, the importance of genetic determinants of RHR has been recently suggested, but it needs to be further investigated. OBJECTIVE: The aim of this study was to estimate the contribution of common genetic variations on RHR using Genome Wide Association Study. METHODS: We performed a Genome Wide Association Study in an isolated population cohort of 1737 individuals, the Italian Network on Genetic Isolates - Friuli Venezia Giulia (INGI-FVG). Moreover, a haplotype analysis was performed. A regression tree analysis was run to highlight the effect of each haplotype combination on the phenotype. RESULTS: A significant level of association (p<5 × 10(-8)) was detected for Single Nucleotide Polymorphisms (SNPs) in two genes expressed in the heart: MAML1 and CANX. Founding that the three different variants of the haplotype, which encompass both genes, yielded a phenotypic correlation. Indeed, a haplotype in homozygosity is significantly associated with the lower quartile of RHR (RHR ≤ 58 bpm). Moreover no significant association was found between cardiovascular risk factors and the different haplotype combinations. CONCLUSION: Mastermind-like 1 and Calnexin were found to be associated with RHR. We demonstrated a relation between a haplotype and the lower quartile of RHR in our populations. Our findings highlight that genetic determinants of RHR may be implicated in determining cardiovascular diseases and could allow a better risk stratification.