RESUMO
This review explores gender disparities in cardiac electrophysiology, highlighting differences in the electrical activity of the heart between men and women. It emphasizes the importance of understanding these variances for correct diagnosis and effective treatment of cardiac arrhythmias. Women show distinct cardiac characteristics influenced by sex hormones, affecting their susceptibility to various arrhythmias. The manuscript covers the classification, mechanisms, and management of arrhythmias in women, considering factors such as pregnancy and menopause. By addressing these gender-specific nuances, it aims to improve healthcare practices and outcomes for female patients with cardiac rhythm disorders.
Esta revisión explora las disparidades de género en la electrofisiología cardiaca, destacando las diferencias en la actividad eléctrica del corazón entre hombres y mujeres. Se enfatiza la importancia de comprender estas variaciones para un diagnóstico correcto y un tratamiento efectivo de las arritmias cardiacas. Las mujeres muestran características cardiacas distintas influenciadas por las hormonas sexuales, lo que afecta su susceptibilidad a diversas arritmias. La revisión abarca la clasificación, los mecanismos y el manejo de las arritmias en las mujeres, considerando factores como el embarazo y la menopausia. Al abordar estos matices específicos de género, el objetivo es mejorar las prácticas de atención médica y los resultados para las pacientes de sexo femenino con trastornos del ritmo cardiaco.
Assuntos
Arritmias Cardíacas , Humanos , Feminino , Arritmias Cardíacas/fisiopatologia , Arritmias Cardíacas/diagnóstico , Fatores Sexuais , Gravidez , Masculino , Hormônios Esteroides Gonadais , Menopausa/fisiologia , Disparidades em Assistência à SaúdeRESUMO
The aim of this study was to establish whether bumetanide can abort an acute attack of weakness in patients with HypoPP. This was a randomised, double-blind, cross-over, placebo-controlled phase II clinical trial. Focal attack of weakness was induced by isometric exercise of ADM followed by rest (McManis protocol). Participants had two study visits and received either placebo or 2 mg bumetanide at attack onset (defined as 40 % decrement in the abductor digiti minimi CMAP amplitude from peak). CMAP measurements assessed attack severity and duration. Nine participants completed both visits. CMAP percentage of peak amplitudes in the bumetanide (40.6 %) versus placebo (34.9 %) group at 1hr following treatment did not differ significantly (estimated effect difference 5.9 % (95 % CI: (-5.7 %; 17.5 %), p = 0.27, primary outcome). CMAP amplitudes assessed by the area under the curve for early (0-2hr post-treatment) and late (2-4 h post-treatment) efficacy were not statistically different between bumetanide and placebo (early effect estimate 0.043, p = 0.3; late effect estimate 0.085, p = 0.1). Two participants recovered from the attack following bumetanide intake; none recovered following placebo. Bumetanide was well tolerated but not efficacious to rescue a focal attack in an immobilised hand in the majority of patients, although data supports further studies of this agent.
Assuntos
Paralisia Periódica Hipopotassêmica , Humanos , Bumetanida/farmacologia , Bumetanida/uso terapêutico , Músculo Esquelético , Mãos , Extremidade Superior , Método Duplo-CegoRESUMO
Myotonia congenita is a hereditary muscle disease mainly characterized by muscle hyperexcitability, which leads to a sustained burst of discharges that correlates with the magnitude and duration of involuntary aftercontractions, muscle stiffness, and hypertrophy. Mutations in the chloride voltage-gated channel 1 (CLCN1) gene that encodes the skeletal muscle chloride channel (ClC-1) are responsible for this disease, which is commonly known as myotonic chloride channelopathy. The biophysical properties of the mutated channel have been explored and analyzed through in vitro approaches, providing important clues to the general function/dysfunction of the wild-type and mutated channels. After an exhaustive search for CLCN1 mutations, we report in this review more than 350 different mutations identified in the literature. We start discussing the physiological role of the ClC-1 channel in skeletal muscle functioning. Then, using the reported functional effects of the naturally occurring mutations, we describe the biophysical and structural characteristics of the ClC-1 channel to update the knowledge of the function of each of the ClC-1 helices, and finally, we attempt to point out some patterns regarding the effects of mutations in the different helices and loops of the protein.
RESUMO
Sodium voltage-gated channel α subunit 5 (SCN5A)-mutations may cause an array of arrhythmogenic syndromes most frequently as an autosomal dominant trait, with incomplete penetrance, variable expressivity and male predominance. In the present study, we retrospectively describe a group of Mexican patients with SCN5A-disease causing variants in whom the onset of symptoms occurred in the pediatric age range. The study included 17 patients with clinical diagnosis of primary electrical disease, at least one SCN5A pathogenic or likely pathogenic mutation and age of onset <18 years, and all available first- and second-degree relatives. Fifteen patients (88.2%) were male, and sixteen independent variants were found (twelve missense, three truncating and one complex inframe deletion/insertion). The frequency of compound heterozygosity was remarkably high (3/17, 17.6%), with early childhood onset and severe disease. Overall, 70.6% of pediatric patients presented with overlap syndrome, 11.8% with isolated sick sinus syndrome, 11.8% with isolated Brugada syndrome (BrS) and 5.9% with isolated type 3 long QT syndrome (LQTS). A total of 24/45 SCN5A mutation carriers were affected (overall penetrance 53.3%), and penetrance was higher in males (63.3%, 19 affected/30 mutation carriers) than in females (33.3%, 5 affected/15 carriers). In conclusion, pediatric patients with SCNA-disease causing variants presented mainly as overlap syndrome, with predominant loss-of-function phenotypes of sick sinus syndrome (SSS), progressive cardiac conduction disease (PCCD) and ventricular arrhythmias.
Assuntos
Canalopatias/genética , Coração/fisiologia , Canal de Sódio Disparado por Voltagem NAV1.5/genética , Adolescente , Arritmias Cardíacas/genética , Síndrome de Brugada/genética , Doença do Sistema de Condução Cardíaco/genética , Criança , Pré-Escolar , Feminino , Heterozigoto , Humanos , Lactente , Síndrome do QT Longo/genética , Masculino , Mutação/genética , Penetrância , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Estudos Retrospectivos , Síndrome do Nó Sinusal/genéticaRESUMO
Brief resolved unexplained events (BRUEs) have numerous and varied causes posing a challenge to investigation and management. A subset of infants with the neuromuscular disorder sodium channel myotonia, due to mutations in the SCN4A gene, experience apnoeic events due to laryngospasm (myotonia) of the upper airway muscles that may present as a BRUE. We sought to ascertain the frequency, severity and outcome of infants carrying the G1306E SCN4A mutation commonly associated with this presentation. We report 12 new cases of individuals with the G1306E mutation from three unrelated families and perform a literature review of all published cases. Infants with the G1306E mutation almost universally experience laryngospasm and apnoeic events. The severity varies significantly, spans both low and high-risk BRUE categories or can be more severe than criteria for a BRUE would allow. At least a third of cases require intensive care unit (ICU) care. Seizure disorder is a common erroneous diagnosis. Apnoeas are effectively reduced or abolished by appropriate treatment with anti-myotonic agents. Probands with the G1306E mutation who are family planning need to be counselled for the likelihood of post-natal complications. There is readily available and extremely effective treatment for the episodic laryngospasm and apnoea caused by this mutation. Proactively seeking clinical evidence of myotonia or muscle hypertrophy with consideration of CK and EMG in high risk BRUEs or more complex apnoeic events may reduce avoidable and prolonged ICU admissions, patient morbidity and potentially mortality.
RESUMO
OBJECTIVES: To evaluate the clinical features of erythromelalgia in childhood associated with gain-of-function SCN9A mutations that increase activity of the Nav1.7 voltage-gated sodium channel, we conducted a systematic review of pediatric presentations of erythromelalgia related to SCN9A mutations, and compared pediatric clinical presentations of symptomatic erythromelalgia, with or without SCN9A mutations. STUDY DESIGN: PubMed, Embase, and PsycINFO Databases were searched for reports of inherited erythromelalgia in childhood. Clinical features, management, and genotype were extracted. Case notes of pediatric patients with erythromelalgia from the Great Ormond Street Hospital Pain Service were reviewed for clinical features, patient-reported outcomes, and treatments. Children aged over 10 years were recruited for quantitative sensory testing. RESULTS: Twenty-eight publications described erythromelalgia associated with 15 different SCN9A gene variants in 25 children. Pain was severe and often refractory to multiple treatments, including nonspecific sodium channel blockers. Skin damage or other complications of cold immersion for symptomatic relief were common (60%). SCN9A mutations resulting in greater hyperpolarizing shifts in Nav1.7 sodium channels correlated with symptom onset at younger ages (P = .016). Variability in reporting, and potential publication bias toward severe cases, limit any estimations of overall prevalence. In our case series, symptoms were similar but comorbidities were more common in children with SCN9A mutations. Quantitative sensory testing revealed marked dynamic warm allodynia. CONCLUSIONS: Inherited erythromelalgia in children is associated with difficult-to-manage pain and significant morbidity. Standardized reporting of outcome and management in larger series will strengthen identification of genotype-phenotype relationships. More effective long-term therapies are a significant unmet clinical need.
Assuntos
Eritromelalgia/complicações , Eritromelalgia/genética , Mutação/genética , Canal de Sódio Disparado por Voltagem NAV1.7/genética , Dor/etiologia , Adolescente , Criança , Feminino , Humanos , Masculino , Estudos Retrospectivos , Avaliação de SintomasRESUMO
ResumenMuerte súbita se define como un evento fatal e inesperado que ocurre en un individuo aparentemente sano. Una de las principales causas son las de origen cardiovascular, entre las cuales se encuentran las anormalidades electrofisiológicas primarias como lo es el síndrome de Brugada. Este se define como una canalopatía que afecta canales de sodio, producto de una variante genética, principalmente de herencia autosómica dominante.Se ha determinado que la mutación del gen SCN5A es la más asociada con el síndrome. El diagnóstico se realiza mediante historia clínica y patrones electrocardiográficos específicos y generalmente se presenta como síncope o como muerte súbita resucitada debida a taquicardia ventricular polimórfica o fibrilación ventricular. El desfibrilador automático implantable es la principal herramienta para la prevención de muerte súbita, sin embargo, previo a su uso debe hacerse una adecuada estratificación de los pacientes, tanto para prevenir muerte súbita, como para evitar el uso innecesario del dispositivo.
AbstractSudden death is defined as an unexpected fatal event occurring in an apparently healthy subject. Sudden cardiac death is a leading cause, among which are primary electrical abnormalities such as Brugada Syndrome. Brugada Syndrome is an autosomal dominant channelopathy affecting the sodium channel. SCN5A has emerged as the most common gene associated with Brugada syndrome. The diagnosis is suggested by the clinical history in a patient with specific electrocardiographic pattern. The most typical presentation is syncope or resuscitated sudden death due to polymorphic ventricular tachycardia or ventricular fibrillation. An implantable cardioverter defibrillator is the main tool for preventing sudden death, and correct risk stratification in these patients is important both to prevent sudden death and to avoid unnecessary implantable cardioverter defibrillator use.
Assuntos
Humanos , Morte Súbita Cardíaca , Morte Súbita , Síndrome de Brugada , Síndrome de Brugada/epidemiologia , Canalopatias , Medicina LegalRESUMO
La parálisis periódica hiperpotasémica es una canalopatía del músculo esquelético que se caracteriza por episodios recurrentes de debilidad muscular que pueden ser desencadenados por el ejercicio, el frío, el reposo poco después del ejercicio y el aporte de potasio. Se presenta el caso de una paciente de 13 años de edad, con diagnóstico de parálisis periódica hiperpotasémica, sin antecedentes familiares de esta entidad y sin miotonía asociada. Los ataques de debilidad muscular sucedían en ocasiones diariamente y cada 2 o 3 días, con duración variable desde media hora hasta 24 a 48 h. Durante un episodio de debilidad muscular se constataron concentraciones de potasio en sangre de 7,14 mmol/L y el electromiograma mostró un patrón miopático. Se observó una disminución de la frecuencia de los episodios de debilidad muscular a los 2 meses de iniciado el tratamiento con acetazolamida por vía oral(AU)
The periodic hyperpotassemia paralysis is a striated muscle channelopathy characterized by recurrent episodes of muscular asthenia that may to be triggered by exercise, cold, not rest after exercise and potassium support. This the case of a female patient aged 13 diagnosed with hyperpotassemia periodic paralysis without family backgrounds of this entity and also without associated myotonia. The seizures of muscular asthenia occurred almost daily and each 2 or 3 days with a variable length from a half hour to 24 to 48 hours. During a episode of muscular asthenia there were blood potassium concentrations of 7,14 mmol/L and the electromyogram showed a myopathic pattern. There was a frequency decrease of episodes of muscular asthenia at 2 months of treatment onset with oral acetazolamide(AU)
Assuntos
Humanos , Adolescente , Paralisia Periódica Hiperpotassêmica/tratamento farmacológico , Acetazolamida/uso terapêutico , Relatos de CasosRESUMO
La parálisis periódica hiperpotasémica es una canalopatía del músculo esquelético que se caracteriza por episodios recurrentes de debilidad muscular que pueden ser desencadenados por el ejercicio, el frío, el reposo poco después del ejercicio y el aporte de potasio. Se presenta el caso de una paciente de 13 años de edad, con diagnóstico de parálisis periódica hiperpotasémica, sin antecedentes familiares de esta entidad y sin miotonía asociada. Los ataques de debilidad muscular sucedían en ocasiones diariamente y cada 2 o 3 días, con duración variable desde media hora hasta 24 a 48 h. Durante un episodio de debilidad muscular se constataron concentraciones de potasio en sangre de 7,14 mmol/L y el electromiograma mostró un patrón miopático. Se observó una disminución de la frecuencia de los episodios de debilidad muscular a los 2 meses de iniciado el tratamiento con acetazolamida por vía oral
The periodic hyperpotassemia paralysis is a striated muscle channelopathy characterized by recurrent episodes of muscular asthenia that may to be triggered by exercise, cold, not rest after exercise and potassium support. This the case of a female patient aged 13 diagnosed with hyperpotassemia periodic paralysis without family backgrounds of this entity and also without associated myotonia. The seizures of muscular asthenia occurred almost daily and each 2 or 3 days with a variable length from a half hour to 24 to 48 hours. During a episode of muscular asthenia there were blood potassium concentrations of 7,14 mmol/L and the electromyogram showed a myopathic pattern. There was a frequency decrease of episodes of muscular asthenia at 2 months of treatment onset with oral acetazolamide
RESUMO
Ion channels serve diverse cellular functions, mainly in cell signal transduction. In endocrine cells, these channels play a major role in hormonal secretion, Ca2+-mediated cell signaling, transepithelial transport, cell motility and growth, volume regulation and cellular ionic content and acidification of lysosomal compartments. Ion channel dysfunction can cause endocrine disorders or endocrine-related manifestations, such as pseudohypoaldosteronism type 1, Liddle syndrome, Bartter syndrome, persistent hyperinsulinemic hypoglycemia of infancy, neonatal diabetes mellitus, cystic fibrosis, Dent's disease, hypomagnesemia with secondary hipocalcemia, nephrogenic diabetes insipidus and, the most recently genetically identified channelopathy, thyrotoxic hypokalemic periodic paralysis. This review briefly recapitulates the membrane action potential in endocrine cells and offers a short overview of known endocrine channelopathies with focus on recent progress regarding the pathophysiological mechanisms and functional genetic defects.
Canais iônicos auxiliam diferentes funções celulares, principalmente na transdução de sinal. Nas células endócrinas, esses canais têm funções importantes na secreção hormonal, sinalização do Ca2+, transporte transepitelial, regulação da motilidade, volume e conteúdo iônico celular e da acidificação do compartimento lisossomal (pH). Como esperado, as alterações nos canais iônicos podem causar distúrbios endocrinológicos, como pseudo-hipoaldosteronismo tipo 1, síndrome de Liddle, síndrome de Bartter, hipoglicemia hiperinsulinêmica da infância, diabetes melito neonatal, fibrose cística, doença de Dent, hipomagnesemia com hipocalcemia secundária, diabetes insípido nefrogênico e paralisia periódica tirotóxica hipocalêmica. Este artigo propõe uma breve revisão das canalopatias endócrinas conhecidas, com foco particular nos recentes progressos no conhecimento dos mecanismos fisiopatológicos adquirido a partir das alterações funcionais encontradas.
Assuntos
Humanos , Canalopatias , Doenças do Sistema Endócrino , Canais Iônicos , Canalopatias/genética , Canalopatias/fisiopatologia , Doenças do Sistema Endócrino/genética , Doenças do Sistema Endócrino/fisiopatologia , Canais Iônicos/genética , Canais Iônicos/fisiologiaRESUMO
We report a case of a 29-year old man who initially presented with a single episode of syncope. The initial electrocardiogram (ECG) showed atrial fibrillation and an ST segment elevation on lead V1. A flecainide test unmasked the Brugada syndrome. The pathophysiology of Brugada syndrome and atrial fibrillation in this patient could be connected by sodium channel dysfunction throughout the heart. In addition, we reviewed the possible connection between Brugada syndrome and atrial fibrillation.
Reportamos el caso de un hombre de 29 años de edad que se presentó inicialmente con un solo episodio de síncope. El electrocardiograma inicial (ECG) mostró fibrilación atrial y una elevación del segmento ST en la derivación V1. Una prueba de flecainida reveló la presencia del síndrome de Brugada. La patofisiología del síndrome de Brugada y la fibrilación atrial en este paciente podrían estar conectados por una disfunción del canal de sodio a través del corazón. Además, examinamos la posible conexión entre el síndrome de Brugada y la fibrilación atrial.
Assuntos
Adulto , Humanos , Masculino , Fibrilação Atrial/complicações , Síndrome de Brugada/complicações , Taquicardia Supraventricular/complicações , Fibrilação Atrial/fisiopatologia , Síndrome de Brugada/fisiopatologia , EletrocardiografiaRESUMO
Myotonia congenita is a muscular disease characterized by myotonia, hypertrophy, and stiffness. It is inherited as either autosomal dominant or recessive known as Thomsen and Becker diseases, respectively. Here we confirm the clinical diagnosis of a family diagnosed with a myotonic condition many years ago and report a new mutation in the CLCN1 gene. The clinical diagnosis was established using ocular, cardiac, neurological and electrophysiological tests and the molecular diagnosis was done by PCR, SSCP and sequencing of the CLCN1 gene. The proband and the other affected individuals exhibited proximal and distal muscle weakness but no hypertrophy or muscular pain was found. The myotatic reflexes were lessened and sensibility was normal. Electrical and clinical myotonia was found only in the sufferers. Slit lamp and electrocardiogram tests were normal. Two affected probands presented diminution of the sensitive conduction velocities and prolonged sensory distal latencies. The clinical spectrum for this family is in agreement with a clinical diagnosis of Becker myotonia. This was confirmed by molecular diagnosis where a new disease-causing mutation (Q412P) was found in the family and absent in 200 unaffected chromosomes. No latent myotonia was found in this family; therefore the ability to cause this subclinical sign might be intrinsic to each mutation. Implications of the structure-function-genotype relationship for this and other mutations are discussed. Adequate clinical diagnosis of a neuromuscular disorder would allow focusing the molecular studies toward the confirmation of the initial diagnosis, leading to a proper clinical management, genetic counseling and improving in the quality of life of the patients and relatives.
La miotonía congénita es una enfermedad muscular caracterizada por miotonía, hipertrofia y rigidez. Se presenta con dos patrones de herencia, autosómica dominante en cuyo caso recibe el nombre de miotonía de Thomsen, o autosómica recesiva conocida como miotonía de Becker. En este trabajo se confirmó el diagnóstico clínico presuntivo hecho hace algunos años en una familia con una condición miotónica y se reporta una nueva mutación en el gen CLCN1. El diagnóstico clínico se estableció después de estudios oculares, cardíacos, neurológicos y electrofisiológicos. El diagnóstico molecular fue hecho mediante la PCR, SSCP y secuenciación del gen CLCN1. El caso índice y los otros individuos afectados exhibieron debilidad muscular proximal y distal, pero no se encontró hipertrofia ni dolor muscular. Los reflejos miotáticos estuvieron disminuidos y la sensibilidad fue normal. Se encontró miotonía clínica y eléctrica solo en los individuos afectados. Las pruebas de lámpara de hendidura y electrocardiograma resultaron normales. Dos individuos afectados presentaron disminución de las velocidades de conducción sensitiva y latencias distales sensoriales prolongadas. El cuadro clínico concuerda con la miotonía de Becker, lo cual se confirmó con el hallazgo de una mutación responsable de la enfermedad en el gen CLCN1 (Q412P), la cual se encontró en la familia y estuvo ausente en 200 cromosomas provenientes de la población general. No se encontró miotonía latente, por lo que probablemente la habilidad de causar este signo subclínico es intrínsica de cada mutación. Afinar el diagnóstico clínico diferencial de las enfermedades neuromusculares permitiría enfocar los estudios moleculares hacia la confirmación del diagnóstico inicial en forma eficiente, lo cual permitiría un manejo clínico y asesoramiento genético más adecuados y una mejora en la calidad de vida de los pacientes y sus familias.