Cardiac Channelopathies Research Articles

Cochlear implantation in children with congenital long QT syndrome: Introduction of an evidence-based pathway of care

Congenital long QT syndrome (cLQTS) is an inherited cardiac ion channelopathy characterized by a long corrected-QT interval on the ECG, associated with a risk of syncope and sudden death as a result of arrhythmias. The archetypal arrhythmia associated with cLQTS is torsade de pointes which may degenerate into ventricular fibrillation. Children with Jervell and Lange-Neilsen syndrome have the combination of cLQTS and congenital sensorineural deafness and may present for cochlear implantation (CI). Sympathetic stimulation and administration of QT-prolonging medications may trigger arrhythmias in children with cLQTS and thus the perioperative period is a time of increased risk of adverse events, with deaths reported in the CI literature. Our Paediatric Cochlear Implant Programme had previously elected to discontinue offering CI to children with cLQTS following a perioperative death. However, subsequent demand for this service by parents led us to develop and introduce a multidisciplinary, evidence-based pathway of care. This pathway modifies the perioperative management of these children to reduce the associated risk. We present the cases of four children with cLQTS who underwent CI in our specialist children’s hospital.

Seizure-like episodes and EEG abnormalities in patients with long QT syndrome

PurposeThe congenital long QT-syndrome (cLQTS) is characterized by ventricular arrhythmias, syncope and sudden cardiac death. Many LQTS genes are also expressed in the brain and emerging evidence suggest that cardiac channelopathies can also cause epilepsy. The aim of the study is to explore evidence of epilepsy and/or EEG abnormalities in a cohort with a genotyped diagnosis of LQT1 or LQT2. MethodsAdult patients were randomly selected from the outpatient clinic and a random sample of healthy controls were recruited from the general population. Ictal semiology was explored in symptomatic patients. A 1 h 64-channel awake EEG was performed and analyzed by visual assessment. Brain connectivity was quantified by Directed Transfer Function (DTF) from the current source density estimate within the theta band (4–7 Hz). ResultsFifteen patients with LQT1, 20 with LQT2 and 20 controls were included. Seventy-one % of the patients reported loss of consciousness (LOC); 44% in combination with convulsions. EEG was abnormal in 34% of patients and 10% of controls (p < 0.05). Two patients had epileptiform or sharp activity. The fronto-parietal DTF connectivity was significantly altered in patients compared to controls (LQT1 p = 2.2 × 10−6, LQT2 p = 0.044). ConclusionSeizure-like episodes and EEG abnormalities were common in our cohort with cLQTS patients. However, we could not find firm evidence of epilepsy.Our findings reinforce the notion that cLQTS is a cardiocerebral channelopathy. Correct classification of seizures may be challenging to the clinician, but of vital importance for patients.

TRPM4 mutations to cause autosomal recessive and not autosomal dominant Brugada type 1 syndrome

Cardiac channelopathies, mainly Long QT and Brugada syndromes, are genetic disorders for which genotype/phenotypes relationships remains to be improved. To provide new insights into the Brugada syndrome pathophysiology, a mutational study was performed on a 64-year-old man presented with isolated exertional dyspnea (NYHA class: II-III), hypertension, chronic kidney disease, coronary disease, an electrocardiogram suggesting a Brugada type 1-like pattern with ST-segment elevation in leads V1-V2. Molecular diagnosis study was performed using molecular strategy based on the sequencing of a panel of 19 Brugada-associated genes. The proband was carrier of 2 TRPM4 null alleles [IVS9+1G > A and p. Trp525X] resulting in the absence of functional hTRPM4 proteins. Due to this unexpected genotype, meta-analysis of previously reported TRPM4 variations associated with cardiac pathologies was performed using ACMG guidelines. All were detected in a heterozygous status. This additional meta-analysis indicated that most of them could not be considered definitely as pathogen. In conclusion, our study reports, for the first time, identification of compound heterozygous TRPM4 null mutations in a proband with, at an arrhythmogenic level, only a Brugada type 1-like electrocardiogram. By combining the genotype/phenotype relationship of this case and analysis of previously reported TRPM4 variations, we suggest that loss-of-function TRPM4 variations, in a heterozygous status, could not be considered as pathogenic or likely pathogenic mutations in cardiac channelopathies such as Long QT syndrome or Brugada syndrome.

Abstract 256: Precision Medicine in Cardiac Channelopathy: Integrating Genome Editing and Induced Pluripotent Stem Cells to Decipher Variant of Unknown Significance

Background: The long QT syndrome (LQTS) is an arrhythmogenic disorder of QT interval prolongation that predisposes patients to life-threatening ventricular arrhythmias such as Torsade de pointes (TdP) and sudden cardiac death (SCD). Clinical genetic testing has emerged as the standard of care to identify genetic variants in patients suspected of having LQTS. However, these results are often confounded by the discovery of variants of unknown significance (VUS), for which there is insufficient evidence of pathogenicity. Objectives: To demonstrate that genome editing of patient-specific induced pluripotent stem cells (iPSCs) can be a valuable approach to delineate the pathogenicity of VUS in cardiac channelopathy. Methods and Results: Peripheral blood mononuclear cells (PBMCs) were isolated from a carrier with a novel missense variant (T983I) in the KCNH2 (LQT2) gene and an unrelated healthy control subject. iPSCs were generated using an integration-free Sendai virus and differentiated to iPSC-derived cardiomyocytes (iPSC-CMs). Whole-cell patch clamp recordings revealed significant prolongation of the action-potential duration (APD) and reduced rapidly activating delayed rectifier K + current ( I Kr ) density in VUS iPSC-CMs compared to healthy control iPSC-CMs. ICA-105574, a potent I Kr activator, enhanced I Kr magnitude and restored normal APD in VUS iPSC-CMs. Notably, VUS iPSC-CMs exhibited greater propensity to proarrhythmia than healthy control cells in response to high-risk torsadogenic drugs (dofetilide, ibutilide, and azimilide), suggesting a compromised repolarization reserve. Finally, the selective correction of the causal variant in iPSC-CMs using CRISPR/Cas9 gene editing (isogenic control) normalized the aberrant cellular phenotype, whereas the introduction of the homozygous variant in healthy control cells recapitulated hallmark features of the LQTS disorder. Conclusions: Our results suggest that the KCNH2 T983I VUS may be classified as potentially pathogenic.

Wearable cardioverter defibrillators for patients with long QT syndrome

BackgroundLong QT syndrome (LQTS) is a potentially lethal cardiac channelopathy, but with the appropriate treatment strategy, such as beta-blockers, left cardiac sympathetic denervation (LCSD), and/or an implantable cardioverter defibrillator (ICD), most LQTS-triggered tragedies can be avoided. Since 2001, wearable cardioverter defibrillators (WCD:LifeVest™) have been available clinically. ObjectiveHerein, we evaluated the use and outcome of WCDs in patients with LQTS. MethodsWe performed a retrospective review of 1027 patients with LQTS to identify patients who received a WCD, and collected pertinent clinical information regarding their LQTS diagnosis as well as indication and experience regarding use of the WCD. ResultsOverall, 10 LQTS patients (1%, 8 females, age at diagnosis 29 ± 18 years, mean QTc 488 ± 34 ms) were prescribed a WCD. Most common indication for WCD was as bridge to treatment during (temporary) situation of assessed high risk of sudden cardiac arrest (SCA; n = 6). The mean time of WCD use was 24 days (range 0 to 114 days). One patient (female, age 42, LQT2) received an appropriate VF-terminating shock 2 days after receiving her WCD. No inappropriate treatments or adverse events from wearing the WCD have occurred. ConclusionsA WCD can be considered in patients with LQTS deemed to be at high risk for SCA while up-titrating beta blockers, considering ICD therapy, or when navigating short term periods of increased SCA-risk, like the post-partum period in LQT2 women, ICD revision or temporary inactivation, or during short term administration of known QT prolonging medications.

Human Induced Pluripotent Stem Cell–Derived Cardiomyocytes as Models for Cardiac Channelopathies

Life threatening ventricular arrhythmias leading to sudden cardiac death are a major cause of morbidity and mortality. In the absence of structural heart disease, these arrhythmias, especially in the younger population, are often an outcome of genetic defects in specialized membrane proteins called ion channels. In the heart, exceptionally well-orchestrated activity of a diversity of ion channels mediates the cardiac action potential. Alterations in either the function or expression of these channels can disrupt the configuration of the action potential, leading to abnormal electrical activity of the heart that can sometimes initiate an arrhythmia. Understanding the pathophysiology of inherited arrhythmias can be challenging because of the complexity of the disorder and lack of appropriate cellular and in vivo models. Recent advances in human induced pluripotent stem cell technology have provided remarkable progress in comprehending the underlying mechanisms of ion channel disorders or channelopathies by modeling these complex arrhythmia syndromes in vitro in a dish. To fully realize the potential of induced pluripotent stem cells in elucidating the mechanistic basis and complex pathophysiology of channelopathies, it is crucial to have a basic knowledge of cardiac myocyte electrophysiology. In this review, we will discuss the role of the various ion channels in cardiac electrophysiology and the molecular and cellular mechanisms of arrhythmias, highlighting the promise of human induced pluripotent stem cell-cardiomyocytes as a model for investigating inherited arrhythmia syndromes and testing antiarrhythmic strategies. Overall, this review aims to provide a basic understanding of the electrical activity of the heart and related channelopathies, especially to clinicians or research scientists in the cardiovascular field with limited electrophysiology background.

Aberrant Deactivation-Induced Gain of Function in TRPM4 Mutant Is Associated with Human Cardiac Conduction Block

A gain-of-function mutation in the Ca2+-activated transient receptor potential melastatin member 4 (TRPM4A432T) is linked to life-threatening cardiac conduction disturbance, but the underlying mechanism is unclear. For deeper insights, we used photolysis of caged Ca2+, quantitative Ca2+, and electrophysiological measurements. TRPM4A432T's 2-fold larger membrane current was associated with 50% decreased plasma membrane expression. Kinetic analysis unveiled 4-fold slower deactivation that was responsible for the augmented membrane current progressively rising during repetitive human cardiac action potentials. Rational mutagenesis of TRPM4 at position 432 revealed that the bulkiness of the amino acid was key to TRPM4A432T's aberrant gating. Charged amino acids rendered the channel non-functional. The slow deactivation caused by an amino acid substitution at position 432 from alanine to the bulkier threonine represents a key contributor to the gain of function in TRPM4A432T. Thus, our results add a mechanism in the etiology of TRP channel-linked human cardiac channelopathies.

Genome Editing of Induced Pluripotent Stem Cells to Decipher Cardiac Channelopathy Variant

BackgroundThe long QT syndrome (LQTS) is an arrhythmogenic disorder of QT interval prolongation that predisposes patients to life-threatening ventricular arrhythmias such as Torsades de pointes and sudden cardiac death. Clinical genetic testing has emerged as the standard of care to identify genetic variants in patients suspected of having LQTS. However, these results are often confounded by the discovery of variants of uncertain significance (VUS), for which there is insufficient evidence of pathogenicity. ObjectivesThe purpose of this study was to demonstrate that genome editing of patient-specific induced pluripotent stem cells (iPSCs) can be a valuable approach to delineate the pathogenicity of VUS in cardiac channelopathy. MethodsPeripheral blood mononuclear cells were isolated from a carrier with a novel missense variant (T983I) in the KCNH2 (LQT2) gene and an unrelated healthy control subject. iPSCs were generated using an integration-free Sendai virus and differentiated to iPSC-derived cardiomyocytes (CMs). ResultsWhole-cell patch clamp recordings revealed significant prolongation of the action potential duration (APD) and reduced rapidly activating delayed rectifier K+ current (IKr) density in VUS iPSC-CMs compared with healthy control iPSC-CMs. ICA-105574, a potent IKr activator, enhanced IKr magnitude and restored normal action potential duration in VUS iPSC-CMs. Notably, VUS iPSC-CMs exhibited greater propensity to proarrhythmia than healthy control cells in response to high-risk torsadogenic drugs (dofetilide, ibutilide, and azimilide), suggesting a compromised repolarization reserve. Finally, the selective correction of the causal variant in iPSC-CMs using CRISPR/Cas9 gene editing (isogenic control) normalized the aberrant cellular phenotype, whereas the introduction of the homozygous variant in healthy control cells recapitulated hallmark features of the LQTS disorder. ConclusionsThe results suggest that the KCNH2T983I VUS may be classified as potentially pathogenic.

Brugada Syndrome: The Role of Risk Stratification in Selecting Patients for Implantable Cardioverter-defibrillator Placement.

Brugada syndrome (BS) is an inherited cardiac ion channelopathy that is a rare, but treatable, cause of sudden cardiac death (SCD). There are many studies that explore the management of symptomatic BS, but few trials have been conducted regarding management of asymptomatic Brugada patients. Asymptomatic BS patients are shown to be at increased risk (0.5%-1.5%) for SCD compared to the general population and account for nearly 20% of deaths from SCD in patients with structurally normal hearts. Treatment for asymptomatic BS patients is often debated with the current guidelines allowing for management decisions to be made on a case-by-case basis. Therapies include either anti-arrhythmic medications, implantable cardioverter-defibrillator (ICD) placement, or no active treatment. This review intended to assess whether ICD placement benefits asymptomatic BS patients and what criteria may be useful in selecting patients for ICD placement. Results showed that ICD placement can reduce mortality in select asymptomatic patients. There were certain risk factors that increased the likelihood that an asymptomatic patient would experience SCD and thus benefit from an ICD. These factors include an electrocardiogram(ECG) demonstrating spontaneous type 1 Brugada Syndrome and inducibility of ventricular tachyarrhythmias during electrophysiological study. Other variables including gender, family history of SCD, and the presence of SCN5A mutation were not predictive of arrhythmic events. Moreover, many patients can suffer complications from ICDs that can affect the quality of life including inappropriate shocks, device malfunction, infection, mental health problems, and difficulties with replacements. Guidelines for quantifying the risk of SCD relative to the risks associated with ICD placement are still poorly defined. These complications and risk factors should be taken into consideration in the context of a patient-centered discussion regarding ICD placement in asymptomatic patients.

Familiäre Arrhythmieerkrankungen mit strukturell normalen Herzen

ZusammenfassungAngeborene kardiale Ionenkanalerkrankungen/familiäre Arrhythmieerkrankungen sind häufige Ursachen für arrhythmogene Synkopen und den plötzlichen Herztod bei jungen Erwachsenen. Sie sind mittlerweile bei rechtzeitiger Diagnose und adäquater antiarrhythmischer Therapie gut beherrschbar. Der (verbesserten) Risikostratifizierung kommt in der Behandlung eine entscheidende Rolle zu. Da sich das arrhythmogene Risiko mit der Zeit ändern kann, sind regelmäßige Verlaufskontrollen indiziert. Die genetischen und pathophysiologischen Grundlagen werden zunehmend besser verstanden und so gezieltere (mechanismusbasierte) Therapien möglich.

Flecainide-Induced Brugada Syndrome in a Patient With Skeletal Muscle Sodium Channelopathy: A Case Report With Critical Therapeutical Implications and Review of the Literature

Skeletal muscle sodium channelopathies are a group of neuromuscular disorders associated with mutations in the SCN4A gene. Because principal sodium channel isoforms expressed in the skeletal muscles and the heart are distinct one from the other, this condition usually spares cardiac functioning. Nonetheless, evidence on a possible link between skeletal muscle and cardiac sodium channelopathies has emerged in recent years. To date, eight patients bearing pathogenetic mutations in the SCN4A gene and manifesting cardiac electrophysiological alterations have been reported in literature. Among these patients, three presented a phenotype compatible with Brugada syndrome. We report the case of a 29-year-old patient affected by non-dystrophic myotonia associated with a p.G1306E mutation in the SCN4A gene, who presented symptoms of syncope and palpitation after the introduction of flecainide as an anti-myotonic agent. ECG and ajmaline challenge were consistent with the diagnosis of Brugada syndrome, leading to the implantation of a cardioverter defibrillator. No mutation in causative genes for Brugada syndrome was detected. Mexiletine treatment reduced myotonia without any cardiac adverse events. This case report highlights the clinical relevance of the recognition of cardiac electrophysiological alterations in skeletal muscle sodium channelopathies. The discovery of a possible pathogenetic linkage between skeletal muscle and cardiac sodium channelopathies may have significant implications in patients' management, also in light of the fact that class 1C anti-arrhythmics are potential triggers for life-threatening arrhythmias in patients with Brugada syndrome.

Syncopes and channelopathies

Syncope can be the first manifestation of cardiac channelopathies, namely Brugada syndrome, long QT syndrome, short QT syndrome and catecholaminergic polymorphic ventricular tachycardia (CPVT). Patients affected by these rare diseases are at increased risk for sudden cardiac death due to ventricular tachyarrhythmias and require specific therapy and follow-up. As syncope is common in the general population, only few cases are caused by an underlying channelopathy. Nevertheless, the diagnosis should be considered in young patients with structurally normal hearts, especially if the history of syncope is typical for an arrhythmogenic cause, in the presence of characteristic echocardiogram (ECG) patterns, and if there is afamily history of channelopathies or sudden cardiac death. On the other hand, syncope plays an important role in the management of patients with diagnosed channelopathies, as they may indicate an increased risk for sudden cardiac death. The predictive value and consequences for treatment vary between the different channelopathies. However, data on this issue are scarce due to the low prevalence of these diseases. This review highlights typical findings in the medical history and diagnostic tests that may point towards an underlying channelopathy in patients with syncope. It also discusses the prognostic and therapeutic implications of ahistory of syncope in patients with known channelopathies.

Inherited primary arrhythmia disorders: cardiac channelopathies and sports activity.

Sudden cardiac death (SCD) in an apparently healthy individual is atragedy. It is important to identify the cause of death and to prevent SCD in potentially at-risk family members. Inherited primary arrhythmia disorders are associated with exercise-related SCD. Despite the well-known benefits of exercise, exercise restriction has been ahistorical mainstay of therapy for these conditions. However, since familiarity with inherited arrhythmia conditions has increased and patients are often children and young adults, it is necessary to reassess the treatment guidelines regarding exercise constraints. The aim of this review is to analyze the risk of exercise-induced SCD in patients with inherited cardiac conditions and explore the challenges faced when advising patients about exercise limitations. We searched for publications on cardiac channelopathies in PubMed with the following medical subject headings (MeSH): "long QT syndrome"; "short QT syndrome"; "Brugada syndrome"; and "catecholaminergic polymorphic ventricular tachycardia". The abstracts of these articles were scanned, and articles of relevance, along with pertinent references, were read in full. The analysis was restricted to reports published in English. The findings of this analysis suggest that exercise with low-to-moderate cardiovascular demand may be possible under regular clinical follow-up in inherited primary arrhythmia disorders. Recent data show that patients with inherited primary arrhythmia disorders are at low risk for events once acomprehensive treatment program has been established. Recreational activity is likely safe for these individuals, with personalized management based on individual patient preferences and priorities.

Electrophysiologic Considerations After Sudden Cardiac Arrest.

Background:Sudden Cardiac Death (SCD) remains a major public health concern, accounting for more than 50% of cardiac deaths. The majority of these deaths are related to ischemic heart disease, however increasingly recognized are non-ischemic causes such as cardiac channelopathies. Bradyarrhythmias and pulseless electrical activity comprise a larger proportion of out-of-hospital arrests than previously realized, particularly in patients with more advanced heart failure or noncardiac triggers such as pulmonary embolism. Patients surviving Sudden Cardiac Arrest (SCA) have a substantial risk of recurrence, particularly within 18 months post event. The timing of tachyarrhythmias complicating acute infarction has important implications regarding the likelihood of recurrence, with those occurring within 48 hours having a more favorable long-term outcome. In the absence of a clear reversible cause, implantable cardioverter defibrillators remain the mainstay in the secondary prevention of SCD. Post defibrillation electromechanical dissociation is common in patients with cardiomyopathy and can lead to SCD despite successful defibrillation of the primary tachyarrhythmia. Antiarrhythmic agents are highly effective in preventing recurrent arrhythmias in specific diseases such as the congenital long QT syndrome.Conclusion:Catheter ablation is used most commonly to prevent recurrent ICD therapies in patients with structural heart disease-related ventricular arrhythmias, however recent publications have shown substantial benefit in other entities such as idiopathic ventricular fibrillation.

A common co-morbidity modulates disease expression and treatment efficacy in inherited cardiac sodium channelopathy

Management of patients with inherited cardiac ion channelopathy is hindered by variability in disease severity and sudden cardiac death (SCD) risk. Here, we investigated the modulatory role of hypertrophy on arrhythmia and SCD risk in sodium channelopathy. Follow-up data was collected from 164 individuals positive for the SCN5A-1795insD founder mutation and 247 mutation-negative relatives. A total of 38 (obligate) mutation-positive patients died suddenly or suffered life-threatening ventricular arrhythmia. Of these, 18 were aged >40 years, a high proportion of which had a clinical diagnosis of hypertension and/or cardiac hypertrophy. While pacemaker implantation was highly protective in preventing bradycardia-related SCD in young mutation-positive patients, seven of them aged >40 experienced life-threatening arrhythmic events despite pacemaker treatment. Of these, six had a diagnosis of hypertension/hypertrophy, pointing to a modulatory role of this co-morbidity. Induction of hypertrophy in adult mice carrying the homologous mutation (Scn5a1798insD/+) caused SCD and excessive conduction disturbances, confirming a modulatory effect of hypertrophy in the setting of the mutation. The deleterious effects of the interaction between hypertrophy and the mutation were prevented by genetically impairing the pro-hypertrophic response and by pharmacological inhibition of the enhanced late sodium current associated with the mutation. This study provides the first evidence for a modulatory effect of co-existing cardiac hypertrophy on arrhythmia risk and treatment efficacy in inherited sodium channelopathy. Our findings emphasize the need for continued assessment and rigorous treatment of this co-morbidity in SCN5A mutation-positive individuals.

Conservation of cardiac L-type Ca2+ channels and their regulation in Drosophila: A novel genetically-pliable channelopathic model

Dysregulation of L-type Ca2+ channels (LTCCs) underlies numerous cardiac pathologies. Understanding their modulation with high fidelity relies on investigating LTCCs in their native environment with intact interacting proteins. Such studies benefit from genetic manipulation of endogenous channels in cardiomyocytes, which often proves cumbersome in mammalian models. Drosophila melanogaster, however, offers a potentially efficient alternative as it possesses a relatively simple heart, is genetically pliable, and expresses well-conserved genes. Fluorescence in situ hybridization confirmed an abundance of Ca-α1D and Ca-α1T mRNA in fly myocardium, which encode subunits that specify hetero-oligomeric channels homologous to mammalian LTCCs and T-type Ca2+ channels, respectively. Cardiac-specific knockdown of Ca-α1D via interfering RNA abolished cardiac contraction, suggesting Ca-α1D (i.e. A1D) represents the primary functioning Ca2+ channel in Drosophila hearts. Moreover, we successfully isolated viable single cardiomyocytes and recorded Ca2+ currents via patch clamping, a feat never before accomplished with the fly model. The profile of Ca2+ currents recorded in individual cells when Ca2+ channels were hypomorphic, absent, or under selective LTCC blockage by nifedipine, additionally confirmed the predominance of A1D current across all activation voltages. T-type current, activated at more negative voltages, was also detected. Lastly, A1D channels displayed Ca2+-dependent inactivation, a critical negative feedback mechanism of LTCCs, and the current through them was augmented by forskolin, an activator of the protein kinase A pathway. In sum, the Drosophila heart possesses a conserved compendium of Ca2+ channels, suggesting that the fly may serve as a robust and effective platform for studying cardiac channelopathies.

Синдром Бругада и перекрестные синдромы сердечной натриевой каналопатии: различные маски мутаций гена SCN5A

Синдром Бругада и перекрестные синдромы сердечной натриевой каналопатии: различные маски мутаций гена SCN5A

Acquired long QT syndrome and torsade de pointes.

Since its initial description by Jervell and Lange-Nielsen in 1957, the congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS continues to remain the domain of cardiologists, cardiac electrophysiologists, and specialized centers, the by far more frequent acquired drug-induced LQTS is the domain of all physicians and other members of the health care team who are required to make therapeutic decisions. This report will review the electrophysiological mechanisms of LQTS and torsade de pointes, electrocardiographic characteristics of acquired LQTS, its clinical presentation, management, and future directions in the field.

Cardiac Channelopathies: Recognition, Treatment, Management.

The discovery of the human genome has ushered in a new era of molecular testing, advancing our knowledge and ability to identify cardiac channelopathies. Genetic variations can affect the opening and closing of the potassium, sodium, and calcium channels, resulting in arrhythmias and sudden death. Cardiac arrhythmias caused by disorders of ion channels are known as cardiac channelopathies. Nurses are important members of many interdisciplinary teams and must have a general understanding of the pathophysiology of the most commonly encountered cardiac channelopathies, electrocardiogram characteristics, approaches to treatment, and care for patients and their families. This article provides an overview of cardiac channelopathies that nurses might encounter in an array of clinical and research settings, focusing on the clinically relevant features of long QT syndrome, short QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, and arrhythmogenic right ventricular dysplasia/cardiomyopathy.

P791A common co-morbidity modulates disease expression and treatment efficacy in inherited cardiac sodium channelopathy

P791A common co-morbidity modulates disease expression and treatment efficacy in inherited cardiac sodium channelopathy