Triadin knockout syndrome has been defined as a disease with transient long QT, T wave abnormalities, and extremely severe fatal cardiac arrhythmias in young children. In this report, we wanted to share the characteristics of our two cases who presented with sudden cardiac arrest and were diagnosed with triadin knockout syndrome.

Ventricular repolarisation can be influenced by hormonal milieu which may mimic long QT syndrome. We describe a series of patients referred for genetic testing for diagnosed long QT syndrome where a detailed clinical workup demonstrated endocrinopathies as the cause of presumed “gene negative” long QT syndrome and QT prolongation.

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Congenital Long QT Syndrome (LQTS) is a dangerous arrhythmic disorder that can be diagnosed in children with bradycardia. It is characterised by a prolonged QT interval and torsades de pointes that may cause sudden death. Long QT syndrome is an ion channelopathy with complex molecular and physiological infrastructure. Unlike the acquired type, congenital LQTS has a genetic inheritance and it may be diagnosed by syncope, stress in activity, cardiac dysfunction, sudden death or sometimes incidentally. Permanent pacemaker implantation is required for LQTS with resistant bradycardia even in children to resolve symptoms and avoid sudden death.

Cardio-facio-cutaneous syndrome is a genetic anomaly characterised by craniofacial dysmorphia, developmental retardation, skin lesions, mental retardation/learning disability, and cardiac malformations. Cardio-facio-cutaneous syndrome rarely causes arrhythmias and has not been previously associated with long QT in the literature. With this report, it was aimed to draw attention to a different presentation of the long QT syndrome.

A female neonate with in utero selective serotonin reuptake inhibitor exposure presented with bradycardia shortly after birth. Electrocardiography showed severe QT prolongation and second-degree atrioventricular block. Over time QT-times spontaneously normalised and genetic testing did not show mutations associated with long QT syndrome making maternal selective serotonin reuptake inhibitor usage the most likely explanation for the observed severe transient neonatal QT prolongation.

The coexistence of long QT syndrome with 2:1 or complete atrioventricular blocks has been reported in the literature, but, to the best of our knowledge, this is the first pediatric case of long QT syndrome coexisting with first-degree atrioventricular blocks(1–3).

Untreated congenital long QT syndrome may result in potentially lethal ventricular tachycardia. In the most common type, risk of such an event has been linked to exercise. This originally resulted in very restrictive guidelines for sports participation in affected individuals. Although the complex interactions of a specific genotype, modifying cofactors, and risk are only now being explored, scientific evidence based on clinical experience now suggests that in many instances such restrictive guidelines are unwarranted. In particular, patients with this condition who are compliant with β-blocker therapy and who have never had symptoms during exertion are now enjoying the benefits of athletic activity.

The molecular millennium has bestowed clinicians and researchers with the essential tools to identify the underlying genetic substrates for thousands of genetic disorders, most of which are rare and follow Mendelian inheritance patterns. The genetic basis of potentially lethal and heritable cardiomyopathies and cardiac channelopathies has been identified and are now better understood. Genetic testing for several of these heritable conditions has made its transition from discovery through translation and have been commercially available clinical tests for over a decade. Now that clinical genetic testing is available more readily and delivers a disease-specific impact across the triad of medicine – diagnostic, prognostic, and therapeutic – it is important for the community of cardiologists to not only be familiar with the language of genomic medicine but to also be wiser users and even wiser interpreters of genetic testing so that wise decisions can be rendered for those patients and their families being evaluated with respect to the presence or absence of one of these potentially lethal yet highly treatable genetic disorders. The purpose of this review is to provide the reader with a foundational understanding of genetic testing in clinical cardiology. Here, we will present some benefits of genetic testing: indications for either post-mortem genetic testing for the major cardiomyopathies and channelopathies or pre-mortem genetic testing among the decedent’s surviving relatives; the need for careful interpretation of genetic testing results; the importance of genetic counselling; and some points on the ethical and societal implications of genetic testing.

Left thoracic sympathectomy has been shown to be an effective treatment for adults with long QT syndrome who are refractory to medical therapy. We report the successful use of left thoracic sympathectomy for the management of a 10-week-old premature baby with long QT syndrome and heart failure from a large ventricular septal defect and patent ductus arteriosus.

Long QT syndromes encompass the most prevalent group of ion channelopathies. Long QT syndromes are predominantly familial and predispose the affected individual to ventricular arrhythmias and sudden death. Permanent pacemaker insertion for long QT syndrome is discouraged apart from younger patients exhibiting 2:1 atrioventricular block. However, permanent pacemaker insertion is a relatively common procedure in neonates with atrioventricular block, and dual-chamber permanent pacemaker insertion in low birth weight infants is challenging. We describe the management of long QT syndrome − type 2 − presenting in an extremely preterm neonate including epicardial, dual-chamber permanent pacemaker insertion.

We present a case of a previously healthy adolescent male for outpatient evaluation of prolonged QT interval. He was ultimately found to have acquired QT interval prolongation secondary to hypocalcaemia related to undiagnosed hypoparathyroidism. This case report highlights the importance of routine electrolyte analysis, even in the outpatient setting, during initial diagnostic workup for QT interval prolongation.

Type 1 long QT syndrome is the most common long QT syndrome genetic subtype. Exercise and emotional stress can precipitate sudden cardiac events in patients with type 1 long QT syndrome; however, the precise mechanism remains elusive. We report the case of a teenage girl with type 1 long QT syndrome secondary to a rare frameshift mutation (p. L191fs+90X) in the KCNQ1-encoded Kv7.1 potassium channel. During emotional distress, her continuous QTc recordings precipitously increased, peaking within minutes to 669 ms and then returning to baseline (520 ms) as she calmed without concomitant increase in heart rate. This is the first described case documenting transient, marked accentuation of the QTc interval in a long QT syndrome patient during emotional distress. Such events may be triggered by transient accentuation of the intrinsic perturbation in cardiac repolarisation and increase the risk of degeneration to a ventricular arrhythmia. This case illustrates the need improved understanding of the complex interaction between emotion and cardiac stability in patients with long QT syndrome.

This case describes the prenatal diagnosis and integrated peripartum management of a foetus with 2:1 atrioventricular block and torsade de pointes due to congenital long QT syndrome. The unique issues related to the detection of intrauterine conduction abnormalities and ventricular arrhythmias, along with the immediate postnatal care, have been described as an interesting teaching case with successful outcome.

We report a case of a fetus presenting intermittent ventricular tachycardia during midgestation, whose mother had long QT syndrome. The arrhythmia disappeared spontaneously, and the electrocardiogram of the baby after birth showed prolonged QTc. As far as we are aware, this is the first case in which ventricular tachycardia was documented during fetal life in a baby with long QT syndrome.

The prevention of unexpected cardiac events in the young remains elusive. Among them, some are lethal. Early identification of life-threatening arrhythmogenic disorders which often manifest in infancy, childhood or even later, may allow initiation of effective preventive therapies. A large prospective study has indicated that some infants with prolongation of the QT interval in the first week of life died suddenly, and would have previously been labelled as victims of the sudden infant death syndrome. Furthermore, in infants with this diagnosis, post-mortem molecular screening has revealed the presence of the long QT syndrome. As an evolution of this background, some European countries have begun to consider the possibility of introducing in their National Health Services the performance of an electrocardiogram during the first month of life in all newborns, as part of a programme for cardiovascular screening. Most adult cardiologists, however, have no or minimal experience with electrocardiograms recorded in infants. Accordingly, the European Society of Cardiology has instituted a Task Force with the objective of creating guidelines for the interpretation of the neonatal electrocardiogram, focusing on the most clinically relevant abnormalities and on the ensuing options for management and referral. The main objective of the present document is to provide adult cardiologists with a practical approach to neonatal electrocardiography, and paediatricians and neonatologists with a tool that should facilitate medical interaction on cardiologic issues. There are important differences between neonatal and adult electrocardiograms. When a cardiologist examines the electrocardiogram of an apparently normal and healthy infant, the focus has to be on distinguishing between patterns that should cause no alarm, and those that require action or additional investigations. To provide clues for this distinction has been the main objective of the members of this Task Force. Whenever possible or appropriate, we have also suggested steps in management.