RESUMO
Abstract Introduction: Several studies have associated congenital sensorineural hearing loss in children with prolongation of the cardiac parameter QTc. The cause of this association is unknown. At the same time, mutations in GJB2, which encodes connexin 26, are the most common cause of congenital hearing impairment. Objective: To compare electrocardiographic parameters (PR interval, QRS complex, and QTc interval) in patients with hearing loss who were tested for mutations in GJB2 and GJB6 to investigate whether these mutations affect electrical activity of the heart. Methods: 346 patients (176 males, 170 females) with sensorineural hearing loss of 30 dB HL or more, aged 21.8 ± 19.9 years (including 147 children <14 years), underwent both genetic study for GJB2 and GJB6 mutations and electrocardiography. Results: Mutations in GJB2, including homozygotes and heterozygotes, were found in 112 (32%) patients. There were no significant differences in ECG parameters between groups of patients with and without mutations in GJB2. No differences were observed either in men (mean PR with mutation: 155 ± 16.6 vs. 153.6 ± 30.1 without; QRS: 99.9 ± 9.9 vs. 101.1 ± 15.4; QTc: 414.9 ± 29.9 vs. 412.4 ± 25.7) or women (mean PR with: 148.7 ± 21 vs. 143.8 ± 22.8 without; QRS: 94.8 ± 7.6 vs. 92.9 ± 9.6; QTc: 416.8 ± 20.6 vs. 424.9 ± 22.8). In similar fashion, we did we find any significant differences between groups of children with and without GJB2 mutations (mean PR with: 126.3 ± 19.6 vs. 127 ± 19.7 without; QRS: 80.7 ± 9.5 vs. 79.4 ± 11.6; QTc: 419.7 ± 23.5 vs. 419.8 ± 24.8). Conclusion: No association was found between the presence of GJB2 mutations encoding connexin 26 in patients with hearing loss and their ECG parameters (PR, QRS, QTc).
Resumo Introdução: Vários estudos têm associado a perda auditiva neurossensorial congênita em crianças ao prolongamento do parâmetro cardíaco QTc. A causa dessa associação é desconhecida. Ao mesmo tempo, as mutações no GJB2, que codifica a conexina 26, são a causa mais comum de deficiência auditiva congênita. Objetivo: Comparar parâmetros eletrocardiográficos (intervalo PR, complexos QRS e intervalo QTc) em pacientes com perda auditiva que foram testados para mutações no GJB2 e GJB6 para investigar se essas mutações afetam a atividade elétrica do coração. Método: Foram submetidos a estudo genético para mutações de GJB2 e GJB6 e eletrocardiograma 346 pacientes (176 homens, 170 mulheres) com perda auditiva neurossensorial de 30 dB ou mais, com média de 21,8 ± 19,9 anos (incluindo 147 crianças <14 anos). Resultados: Mutações no GJB2, inclusive homozigóticos e heterozigóticos, foram encontradas em 112 (32%) pacientes. Não houve diferenças significativas nos parâmetros de ECG entre grupos de pacientes com e sem mutações no GJB2. Não foram observadas diferenças em homens (PR médio com mutação: 155 ± 16,6 vs. 153,6 ± 30,1 sem mutação; QRS: 99,9 ± 9,9 vs. 101,1 ± 15,4; QTc: 414,9 ± 29,9 vs. 412,4 ± 25,7) nem em mulheres (PR médio com: 148,7 ± 21 vs. 143,8 ± 22,8, sem; QRS: 94,8 ± 7,6 vs. 92,9 ± 9,6; QTc: 416,8 ± 20,6 vs. 424,9 ± 22,8). Da mesma forma, encontramos diferenças significativas entre os grupos de crianças com e sem mutações de GJB2 (PR médio com: 126,3 ± 19,6 vs. 127 ± 19,7, sem; QRS: 80,7 ± 9,5 vs. 79,4 ± 11,6; QTc: 419,7 ± 23,5 vs. 419,8 ± 24,8). Conclusão: Não foi encontrada associação entre a presença de mutações de GJB2 que codificam conexina 26 em pacientes com perda auditiva e seus parâmetros de ECG (PR, QRS, QTc).
Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Síndrome do QT Longo/genética , Conexina 26/genética , Perda Auditiva Neurossensorial/genética , Mutação , Síndrome do QT Longo/complicações , Eletrocardiografia , Genótipo , Perda Auditiva Neurossensorial/complicaçõesRESUMO
INTRODUCTION: Several studies have associated congenital sensorineural hearing loss in children with prolongation of the cardiac parameter QTc. The cause of this association is unknown. At the same time, mutations in GJB2, which encodes connexin 26, are the most common cause of congenital hearing impairment. OBJECTIVE: To compare electrocardiographic parameters (PR interval, QRS complex, and QTc interval) in patients with hearing loss who were tested for mutations in GJB2 and GJB6 to investigate whether these mutations affect electrical activity of the heart. METHODS: 346 patients (176 males, 170 females) with sensorineural hearing loss of 30dB HL or more, aged 21.8±19.9 years (including 147 children <14 years), underwent both genetic study for GJB2 and GJB6 mutations and electrocardiography. RESULTS: Mutations in GJB2, including homozygotes and heterozygotes, were found in 112 (32%) patients. There were no significant differences in ECG parameters between groups of patients with and without mutations in GJB2. No differences were observed either in men (mean PR with mutation: 155±16.6 vs. 153.6±30.1 without; QRS: 99.9±9.9 vs. 101.1±15.4; QTc: 414.9±29.9 vs. 412.4±25.7) or women (mean PR with: 148.7±21 vs. 143.8±22.8 without; QRS: 94.8±7.6 vs. 92.9±9.6; QTc: 416.8±20.6 vs. 424.9±22.8). In similar fashion, we did we find any significant differences between groups of children with and without GJB2 mutations (mean PR with: 126.3±19.6 vs. 127±19.7 without; QRS: 80.7±9.5 vs. 79.4±11.6; QTc: 419.7±23.5 vs. 419.8±24.8). CONCLUSION: No association was found between the presence of GJB2 mutations encoding connexin 26 in patients with hearing loss and their ECG parameters (PR, QRS, QTc).
Assuntos
Conexina 26/genética , Perda Auditiva Neurossensorial/genética , Síndrome do QT Longo/genética , Mutação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Eletrocardiografia , Feminino , Genótipo , Perda Auditiva Neurossensorial/complicações , Humanos , Lactente , Recém-Nascido , Síndrome do QT Longo/complicações , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
BACKGROUND: The aim of the study was to determine, whether electrocardiogram (ECG) screening could reduce the risk of sudden cardiac death in patients with hearing loss through the early diagnosis of Jervell and Lange-Nielsen syndrome and the introduction of the therapy. METHODS: One thousand and eighty patients with hearing loss (aged 21.8 ± 19.9 years) underwent ECG. Additionally, all subjects were asked to complete a 3-question survey. Those who met, at least, one of the high-risk criteria underwent further cardiac assessment and genetic testing. RESULTS: QTc assessment was possible in 1,027 patients. Mean QTc measured 422.8 ± 23.7 ms in 313 women, 414.9 ± 27.7 ms in 273 men and 421.1 ± 21.5 ms in 441 children (individuals younger than 14 years). Abnormal QTc was found in 13 (4.1%) women, 20 (7.3%) men, and 72 (16.3%) children. In the studied group, no recessive mutation of KNCQ1 or KCNE1 was found. In 6 patients, other mutations were found: in KCNQ1 (n = 1), in KCNH2 (n = 3) and in SCN5A (n = 1), which were pathogenic for long-QT-syndromes (LQTS), and 2 mutations of unknown clinical significance in SCN5A. Overall, out of these 6 patients LQTS was diagnosed in 3 asymptomatic patients, but with abnormal QTc and in 2 patients with normal QTc, but who were previously treated for epilepsy. CONCLUSIONS: Jervell and Lange-Nielsen syndrome is a very rare condition even in a population with hearing loss. In this population, the prevalence of prolonged QT interval is increased over the general population. Further investigations are necessary.
Assuntos
Eletrocardiografia , Testes Genéticos , Perda Auditiva Neurossensorial/diagnóstico , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Síndrome de Jervell-Lange Nielsen/diagnóstico , Mutação , Potenciais de Ação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Marcadores Genéticos , Predisposição Genética para Doença , Perda Auditiva Neurossensorial/genética , Perda Auditiva Neurossensorial/fisiopatologia , Testes Auditivos , Humanos , Lactente , Síndrome de Jervell-Lange Nielsen/genética , Síndrome de Jervell-Lange Nielsen/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fenótipo , Polônia , Valor Preditivo dos Testes , Estudos Prospectivos , Fatores de Risco , Inquéritos e Questionários , Adulto JovemRESUMO
We describe a case of a 60 year-old man after inferior wall myocardial infarction with intermittent preexcitation syndrome. In ECG, the pathologic Q waves in the inferior leads were masked by the intermittent preexcitation. In this patient, paroxysmal asymptomatic second-degree atrioventicular block coexists with inconstant atrioventricular conduction maintained by the accessory pathway, periodically 2:1.