ABSTRACT
Abstract Background: To the best of our knowledge, there are studies related to QT and QTc interval in patients with hypocalcemia, but there are no studies evaluating T wave peak and end interval (Tp-e interval), Tp-e/QT and Tp-e/QTc ratios used to evaluate cardiac arrhythmia risk and ventricular repolarization changes rates. Objectives: Therefore, we aimed to investigate whether there is a change in Tp-e interval, Tp-e/QT and Tp-e/QTc ratios in patients with hypocalcemia. Methods: Retrospectively, 29 patients with hypocalcemia in the emergency department were included in the study. Twenty-nine patients with similar age and sex distribution were included in the study as the control group. All patients underwent 12-lead electrocardiography (ECG). In addition to routine measurements, Tp-e interval, Tp-e/QT and Tp-e/QTc ratios were measured on ECG. The study data were grouped as patients with and without hypocalcemia. Results: The mean age of the patients was 66.24 ± 4.95 years. QTc interval, Tp-e interval and Tp-e/QTc values were found to be significantly higher in patients with hypocalcemia (p <0.001 for each). QTc interval, Tp-e interval and Tp-e/QTc ratio showed a significant negative correlation with calcium levels. Conclusion: Tp-e interval and Tp-e/QTc ratios are significantly increased in patients with hypocalcemia compared to those without hypocalcemia and this can be used more effectively in the follow-up of cardiac fatal arrhythmias.
Subject(s)
Humans , Male , Female , Middle Aged , Aged , Arrhythmias, Cardiac/mortality , Long QT Syndrome/complications , Hypocalcemia/complications , Arrhythmias, Cardiac/diagnosis , Retrospective Studies , Electrocardiography/methods , Hypocalcemia/epidemiologyABSTRACT
Abstract: A 67-year-old female patient with a diagnosis of heart failure with preserved ejection fraction secondary to severe mitral regurgitation in treatment with metoprolol, spironolactone, and digoxin. She was diagnosed systemic lupus erythematosus (SLE) because of the presence of arthritis, alopecia, thrombocytopenia, direct positive Coombs +++, positive ANAs 1:1,280 and positive lupus anticoagulant. The rheumatology service indicated hydroxychloroquine 200 mg every 24 hours. She presented atrial fibrillation, and amiodarone was initiated. Two weeks later the patient was admitted because of presyncope, electrocardiogram showed sinus bradycardia with long QT interval. A temporary pacemaker was placed, and hydroxychloroquine and amiodarone suspended. Twenty-four hours later, a new electrocardiogram was taken showing pacemaker rhythm with reduction of the QT interval. After 72 hours the temporary pacemaker was removed and on the fifth day the patient was discharged with an electrocardiogram in sinus rhythm with a corrected QT (Bazett) of 456 miliseconds. The hydroxychloroquine was reinitiated following discharge. She presented another episode of atrial fibrillation, and was treated with amiodarone, hydroxychloroquine was suspended previously, and she did not present prolongation of QT interval. The long QT syndrome was present when amiodarone and hydroxychloroquine interacted.(AU)
Resumen: Paciente femenina de 67 años, con diagnóstico de insuficiencia cardiaca con fracción de expulsión preservada, secundaria a insuficiencia mitral severa, en tratamiento con metoprolol, espironolactona y digoxina. Le fue diagnosticado lupus eritematoso sistémico, debido a la presencia de artritis, alopecia, trombocitopenia, Coombs directo positivo +++, anticuerpos antinucleares positivos 1:1,280 y anticoagulante lúpico positivo. El Servicio de Reumatología indicó hidroxicloroquina 200 mg cada 24 horas. Presentó fibrilación auricular, por lo que se le inició amiodarona. Dos semanas posteriores la paciente es ingresada debido a un episodio de presíncope, se le realizó electrocardiograma que demostró bradicardia sinusal con un intervalo QT prolongado. Se le colocó un marcapasos temporal, además de que se suspendió hidroxicloroquina y amiodarona. Después de 72 horas se retiró el marcapasos, y al quinto día se egresó con un electrocardiograma en ritmo sinusal con el intervalo QT corregido por Bazett de 456 milisegundos. La hidroxicloroquina fue reiniciada al egreso. La paciente presentó otro episodio de fibrilación auricular y fue tratada con amiodarona, previa suspensión de hidroxicloroquina, sin presentar prolongación del intervalo QT. El síndrome de QT largo sólo se presentó con la interacción de amiodarona con hidroxicloroquina.(AU)
Subject(s)
Humans , Female , Aged , Long QT Syndrome/complications , Amiodarone/adverse effects , Hydroxychloroquine/adverse effects , Lupus Erythematosus, Systemic/diagnosisABSTRACT
Resumen Introducción: La prolongación del intervalo QT se asocia con arritmias ventriculares y muerte súbita. Objetivo: Determinar el valor del intervalo QTc en recién nacidos sanos y evaluar su comportamiento durante los primeros meses de vida. Métodos: Recién nacidos sanos a término de marzo-noviembre 2016 en el Hospital General de Occidente del Estado de Jalisco, México. Se les practicó un electrocardiograma de 12 derivaciones a una velocidad de 25 mm/s durante las primeras 48 h. Se midió el intervalo QT en DII y se calculó el QTc mediante la fórmula de Bazett. Los pacientes a los que se detectó prolongación del QTc en sus primeras 48 h se valoraron al mes con ECG y ecocardiograma. Si persistieron con QTc alargado se revaloraron a los 6 meses con ECG, Holter de 24 h y estudio electrocardiográfico a padres y hermanos. Los que persistieron con QTc alargado se revaloraron a los 9 meses con ECG. Resultados: Se incluyeron 548 pacientes. La media del intervalo QTc al nacimiento fue de 459 ms; durante este período 33 pacientes presentaron un QTc mayor de 470 ms, los cuales fueron evaluados al mes mediante un nuevo estudio electrocardiográfico, obteniendo una media del intervalo QTc de 446 ms. A los 6 meses se evaluaron 16 pacientes, con una media del intervalo QTc de 434 ms. A los 9 meses se evaluaron 6 pacientes, con una media del intervalo QTc de 438 ms, y solo 4 pacientes persistieron con QTc prolongado. Conclusiones: El intervalo QTc en nuestros pacientes es más prolongado en comparación con otras poblaciones y muestra una normalización paulatina.
Abstract Introduction: QT interval prolongation is associated with ventricular arrhythmias and sudden death syndrome. Objective: To determine the value of QTc interval in healthy newborns in a general hospital in Jalisco, Mexico, and their outcome during their first months of life. Methods: The study included healthy newborns from March to November 2016, in the Hospital General of Occidente in Jalisco, Mexico. A 12-lead electrocardiogram was performed at a speed of 25 mm/s during the first 48 h of life. The QT interval was measured in lead DII, and the QTc interval was calculated using the Bazett formula. Patients detected with QTc prolongation were assessed monthly with an ECG and echocardiogram. If they persisted with prolonged QTc interval, they were re-evaluated at 6 months with an ECG, 24 h Holter, and electrocardiography study on parents and siblings. Those who persisted with prolonged QTc interval were evaluated with an ECG at 9 months. Results: The study included 548 patients. The mean QTc interval at birth was 459 ms; during this period 33 patients has a QTc greated that 470 ms; which were evaluated monthly with a new electrocardiographic study, obtaining a mean QTc interal of 446 ms. At 6 months 16 patients were evaluated, with a mean QTc interval of 434 ms. At 9 months, 6 patients were found to have a mean QTc interval of 438 ms, and only 4 patients persisted with a prolonged QTc interval. Conclusions: The QTc interval in our population is prolonged compared to other populations and with a gradual return to normal.
Subject(s)
Humans , Male , Female , Infant, Newborn , Arrhythmias, Cardiac/epidemiology , Long QT Syndrome/epidemiology , Death, Sudden/epidemiology , Electrocardiography/methods , Time Factors , Long QT Syndrome/complications , Echocardiography , Pilot Projects , Electrocardiography, Ambulatory/methods , Hospitals, General/methods , Mexico/epidemiologyABSTRACT
Introducción: el síndrome de QT largo es una canalopatía caracterizada por una grave alteración en la repolarización ventricular. Objetivo: determinar los factores de riesgo asociados a intervalo QT prolongado en anestesia cardiovascular. Métodos: estudio descriptivo, de corte transversal desde mayo de 2014 a mayo de 2016, en pacientes programados para cirugía cardíaca bajo circulación extracorpórea. Se evaluó el riesgo atribuible y el intervalo de confianza para un 95 por ciento en variables con p< 0,05. Resultados: se incluyeron 483 pacientes, con una edad media de 62 años, de ellos 57 (12 por ciento) registraron un QTc prolongado. La edad avanzada (RA: 1,8; IC 95 por ciento: 0,86-2,67), insuficiencia renal crónica (RA: 2,7; IC 95 por ciento: 0,82-4,96), diabetes mellitus tipo 2 (RA: 1,7; IC 95 por ciento: 1,01-2,15), cardiopatía isquémica (RA: 3,5; IC 95 por ciento: 1,60-4,02), hipertrofia ventricular izquierda (RA: 2,2; IC 95 por ciento: 2,53-3,15), anticálcicos (RA: 1,5; IC 95 por ciento: 0,92-2,98), anestesia general orotraqueal balanceada (RA: 2,1; IC 95 por ciento: 2,92-2,35), ondansetrón (RA: 1,7; IC 95 por ciento: 0,98-2,74), droperidol (RA: 1,8; IC 95 por ciento: 2,18-3,94), tiempo de circulación extracorpórea (RA: 2,5; IC 95 por ciento: 1,02-3,62), hipopotasemia (RA: 1,4; IC 95 por ciento: 1,03-2,91) y la bradicardia severa (RA: 1,8; IC 95 por ciento: 1,12-3,86) fueron asociados con alto riesgo de prolongación del intervalo QT. Las complicaciones fueron mayores en este grupo, con una mortalidad de 23 por ciento. Conclusiones: la edad avanzada, la insuficiencia renal crónica, diabetes mellitus tipo 2, hipertrofia ventricular y la cardiopatía isquémica facilitan la prolongación del QT inducida por los bloqueadores del calcio. El mayor tiempo de circulación extracorpórea, la anestesia balanceada con isoflurano, el uso de droperidol y ondansetrón, la bradicardia e hipopotasemia posoperatoria son variables asociadas con la extensión del intervalo QT, con un incremento en las complicaciones. Las taquiarritmias ventriculares y la mortalidad fueron mayores en este subgrupo de pacientes(AU)
Introduction: The long QT syndrome is a channelopathy characterized by a serious alteration in ventricular repolarization. Objective: To determine the risk factors associated with prolonged QT interval in cardiovascular anesthesia. Methods: Descriptive, cross-sectional study from May 2014 to May 2016, in patients scheduled for cardiac surgery under extracorporeal circulation. The attributable risk and the confidence interval were evaluated for 95 percent and in variables with p value under 0.05. Results: 483 patients were included, with a mean age of 62 years, of whom 57 (12 percent) had prolonged QTc. Advanced age (RA: 1.8, 95 percent CI: 0.86-2.67), chronic renal failure (RA: 2.7, 95 percent CI: 0.82-4.96), type 2 diabetes mellitus (RA: 1.7, 95 percent CI: 1.01-2.15), ischemic heart disease (RA: 3.5, 95 percent CI: 1.60-4.02), left ventricular hypertrophy (RA: 2.2, 95 percent CI: 2.53-3.15), calcium-lactam antibiotics (RA: 1.5, 95 percent CI: 0.92-2.98), balanced orotracheal general anesthesia (RA: 2.1, 95 percent CI: 2.92-2.35), ondansetron (RA: 1.7, 95 percent CI: 0.98-2.74), droperidol (RA: 1.8, 95 percent CI: 2.18-3.94) ), extracorporeal circulation time (RA: 2.5, 95 percent CI: 1.02-3.62), hypokalemia (RA: 1.4, 95 percent CI: 1.03-2.91) and severe bradycardia (RA: 1.8, 95 percent CI: 1.12-3.86) were associated with a high risk of QT prolongation. The complications were more significant in this group, with a mortality of 23 percent. Conclusions: Advanced age, chronic renal failure, type 2 diabetes mellitus, ventricular hypertrophy, and ischemic heart disease facilitate the prolongation of QT induced by calcium blockers. The longer time of extracorporeal circulation, the balanced anesthesia with isoflurane, the use of droperidol and ondansetron, bradycardia and postoperative hypokalemia are variables associated with the extension of the QT interval, with an increase in complications. Ventricular tachyarrhythmias and mortality were higher in this subgroup of patients(AU)
Subject(s)
Humans , Male , Female , Middle Aged , Long QT Syndrome/complications , Anesthesia, Cardiac Procedures/methods , Anesthesia, General/methods , Long QT Syndrome/epidemiology , Epidemiology, Descriptive , Cross-Sectional Studies , Risk FactorsABSTRACT
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).
Subject(s)
Humans , Male , Female , Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Long QT Syndrome/genetics , Connexin 26/genetics , Hearing Loss, Sensorineural/genetics , Mutation , Long QT Syndrome/complications , Electrocardiography , Genotype , Hearing Loss, Sensorineural/complicationsABSTRACT
La muerte súbita (MS) es un evento trágico que representa un grave problema de salud. Se estima que causa cerca de 4-5 millones de decesos por año en todo el mundo. La MS se define como la muerte ocurrida en el lapso de 1 h en una persona sin signos previos de fatalidad; puede denominarse «recuperada¼, cuando el paciente afectado sobrevive al episodio potencialmente fatal ya sea por reanimación cardiopulmonar o desfibrilación efectiva. Las canalopatías arritmogénicas son alteraciones funcionales de los canales iónicos del corazón, generalmente condicionados por mutaciones en los genes que los codifican y dan lugar a diversos tipos de arritmias que pueden culminar en MS, el deceso ocurre normalmente antes de los 40 años y el corazón en estudio de autopsia suele ser estructuralmente normal. En la presente revisión presentamos las principales causas de MS en el contexto del corazón estructuralmente normal y discutimos el abordaje que se debe dar a los pacientes y familiares de víctimas que han experimentado éste trágico evento.
Sudden death (SD) is a tragic event and a world-wide health problem. Every year, near 4-5 million people experience SD. SD is defined as the death occurred in 1 h after the onset of symptoms in a person without previous signs of fatality. It can be named «recovered SD¼ when the case received medical attention, cardiac reanimation effective defibrillation or both, surviving the fatal arrhythmia. Cardiac channelopathies are a group of diseases characterized by abnormal ion channel function due to genetic mutations in ion channel genes, providing increased susceptibility to develop cardiac arrhythmias and SD. Usually the death occurs before 40 years of age and in the autopsy the heart is normal. In this review we discuss the main cardiac channelopathies involved in sudden cardiac death along with current management of cases and family members that have experienced such tragic event.
Subject(s)
Humans , Death, Sudden, Cardiac/etiology , Arrhythmias, Cardiac/complications , Brugada Syndrome/complications , Death, Sudden, Cardiac/prevention & control , Heart/anatomy & histology , Long QT Syndrome/complications , Reference Values , Tachycardia, Ventricular/complicationsABSTRACT
Se presenta el caso de un lactante con un episodio de pérdida de conocimiento, en quien se diagnosticó fibrilación ventricular. Se realizó desfibrilación externa con éxito, permitiendo luego arribar al diagnóstico etiológico de síndrome de QT prolongado, constituyendo un ejemplo documentado de esta entidad como causa del síndrome de muerte súbita del lactante.
We report the case of an infant with an episode of loss of consciousness, in whom ventricular fibrillation was diagnosed. He was successfully defibrillated and long QT syndrome was diagnosed as his baseline disease. This case constitutes a documented example of this entity as a cause of the sudden infant death syndrome.
Subject(s)
Humans , Infant, Newborn , Male , Brief, Resolved, Unexplained Event/etiology , Long QT Syndrome/complications , Brief, Resolved, Unexplained Event/therapy , Long QT Syndrome/therapy , Pacemaker, Artificial , Sudden Infant Death/etiology , Ventricular Fibrillation/therapyABSTRACT
A Síndrome do QT longo (SQTL) congênito é uma doença dos canais iônicos cardíacos que está associada com síncope, taquiarritmias ventriculares e morte súbita cardíaca em pacientes com coração normal. Raramente, apresenta-se com Bloqueio Atrioventricular 2:1, apresentando mortalidade maior que 50% nos primeiros seis meses de vida, mesmo com tratamento adequado. O caso aqui descrito relata a evolução clínico de lactente com 6 meses de idade com SQTL congênito, síncope de repetição e BAV 2:1 inicialmente tratado como epilepsia, que após tratamento clínico adequado com mudança de estilo de vida, betabloqueadores e implante de marcapasso, não apresentou mais eventos cardíacos. No seguimento tardio (com 6 anos de vida), foi implantado Cardiodesfibrilador Implantável, sem terapias até a presente data.
Congenital long QT syndrome is a disease of cardiac ion channels that is associated withs yncope, cardiac sudden death and ventricular tachyarrhythmias in patients with normal hearts. Rarely,it presents associated with 2:1 atrioventricular block; in this case the mortality rate is higher than 50% in the first six months of life even with adequate treatment. The case described here reports on the clinical evolution of a six-month-old infant with congenital long QT syndrome, syncope of repetition and 2:1 atrioventricular block initially treated as epilepsy, that after the correct clinical treatment with changes in lifestyle, beta-blockers and pacemaker implantation, did not have further cardiac events. In the long term follow-up (six years of life), a defibrillator was implanted without the need of further therapies todate.
Subject(s)
Humans , Male , Infant , Arrhythmias, Cardiac/complications , Arrhythmias, Cardiac/diagnosis , Long QT Syndrome/complications , Death, Sudden , Pacemaker, ArtificialABSTRACT
A síndrome do QT longo (SQTL) congênito é uma doença dos canais iônicos cardíacos que está associada com síncope, taquiarritmias ventriculares e morte súbita cardíaca em pacientes com coração normal. Raramente, apresenta-se com boqueio atrioventricular 2:1, apresentando mortalidade maior que 50% nos primeiros 6 meses de vida, mesmo com tratamento adequado. O caso aqui descrito relata a evolução clínico de lactente com 6 meses de idade com SQTL congênito, síncope de repetição e BAV 2:1 inicialmente tratado como eplepsia, que após tratamento clínico adequado com mudança de estilo de vida, betabloqueadores e implante de marca-passo, não apresentou mais eventos cardíacos. No seguimento tardio (com 6 anos de vida), foi implantado cardiodesfibrilador implantável, sem terapias até a presente data.
Subject(s)
Humans , Infant , Arrhythmias, Cardiac/complications , Arrhythmias, Cardiac/diagnosis , Genetics , Long QT Syndrome/complications , Long QT Syndrome/diagnosis , Death, SuddenABSTRACT
Se realizó un estudio descriptivo, observacional, transversal, con 102 pacientes afectados por síndrome coronario agudo atendidos en la sala de emergencias del Hospital General Docente Leopoldito Martínez de San José de las Lajas, provincia Mayabeque, en el período comprendido desde enero de 2007 hasta diciembre de 2008. Fue medido el intervalo QT en el primer electrocardiograma, se calculó el intervalo QT corregido por la fórmula de Bazett y este fue relacionado con las siguientes variables: sexo, tipo de síndrome coronario agudo, presencia de complicaciones y mortalidad general. Predominaron los pacientes con infarto agudo del miocardio con onda Q mayores de 60 años y del sexo masculino. El intervalo QT corregido máximo estuvo más prolongado en mujeres con infarto agudo del miocardio con onda Q y el QT corregido medio tuvo mayor duración en mujeres con infarto agudo del miocardio sin onda Q. Fueron más frecuentes los pacientes con síndrome coronario agudo que no se complicaron. Entre los que si tuvieron complicaciones predominó el infarto agudo del miocardio con onda Q. El intervalo QT corregido máximo y medio tuvieron una mayor duración en el infarto agudo del miocardio con onda Q sin complicaciones. Predominaron los pacientes con síndrome coronario agudo que no fallecieron. El infarto agudo del miocardio con onda Q tuvo la mayor mortalidad. El QT corregido máximo tuvo mayor duración en pacientes con infarto agudo del miocardio con onda Q que no fallecieron. El valor medio de QT corregido estuvo más prolongado en afectados por infarto agudo del miocardio sin onda Q que no fallecieron. Según la prueba de comparación de medias, no existieron diferencias estadísticamente significativas (p > 0,05; IC: 95 per cent) de los valores medios del QT corregido en relación con el tipo de síndrome coronario agudo, el sexo, las complicaciones y la mortalidad
It was performed a descriptive, transversal study, with 102 patients with acute coronary syndrome (ACS), assisted in the emergency room of the Leopoldito Martínez Teaching Hospital in San José de las Lajas, Mayabeque Province, since january 2007 until december 2008. It was measured the QT interval in the first electrocardiogram, it was calculated QT corrected interval through the Bazett´s formula and it was related with the following variables: age, sex, type of ACS, frequency of complications and overall mortality. There was a predominance of patients with acute myocardial infarction (AMI) with Q wave older than 60 years and male sex. Maximum QTc interval was more elongated in women with Q wave AMI and the average QTc lasted more in women with non-Q wave AMI. ACS Patients without complications were more frequents. It was prevalent the Q wave AMI in complicated patients. Maximum and average QTc intervals lasted more in patients with Q wave AMI without complications. ACS patients who did not decease were more frequent. Mortality was higher in Q wave AMI patients. The maximum QTc interval lasted more in Q wave AMI patients who survived. The average QTc value was more elongated in non-Q wave AMI patients who did not decease. Based on the average comparison test, there was not statistically significant differences (p > 0,05; IC: 95 per cent) between the average values of the QTc interval related to the type of ACS, sex, complications and mortality
Subject(s)
Male , Middle Aged , Angina, Unstable/complications , Angina, Unstable/mortality , Myocardial Infarction/complications , Myocardial Infarction/mortality , Long QT Syndrome/complications , SexSubject(s)
Death, Sudden, Cardiac/etiology , Death, Sudden, Cardiac/prevention & control , Sudden Infant Death/etiology , Sudden Infant Death/prevention & control , Death, Sudden/etiology , Death, Sudden/prevention & control , Cardiomyopathy, Dilated/complications , Cardiomyopathy, Hypertrophic, Familial/complications , Heart Defects, Congenital/complications , Arrhythmogenic Right Ventricular Dysplasia/complications , Risk Factors , Myocardial Ischemia/complications , Brugada Syndrome/complications , Long QT Syndrome/complicationsABSTRACT
Intervalo QT é um parâmetro mensurado pelo eletrocardiograma de superfície que corresponde ao período que vai desde o início da despolarização até o final da repolarização ventricular. Devido à dependência da frequência cardíaca instantânea, o intervalo QT é corrigido pela frequência cardíaca. O intervalo QT corrigido é então empregado na prática clínica, por meio de valores de normalidade. Valores superiores aos recomendados pela literatura revelam o prolongamento significativo do intervalo QT - a síndrome do QT longo - uma desordem da condução elétrica do miocárdio que altera a repolarização ventricular e, consequentemente, aumenta a vulnerabilidade para o desenvolvimento de taquiarritmias ventriculares do tipo torsades de pointes e morte súbita. Esta síndrome pode apresentar origem congênita ou adquirida, com alterações nas propriedades dos canais iônicos de potássio, seja na sua cinética de ativação e inativação seja na densidade da corrente iônica ou mesmo em sua estrutura, resultando no prolongamento do tempo de repolarização ventricular. Assim, o objetivo deste trabalho foi revisar a literatura quanto à descrição ou à caracterização eletrofisiológica dos canais de potássio, em condições normais e relacionadas à síndrome do QT longo.
Subject(s)
Humans , Arrhythmias, Cardiac/diagnosis , Ventricular Function/physiology , Potassium Channels , Long QT Syndrome/complications , Long QT Syndrome/diagnosis , Heart Ventricles/physiopathology , Death, Sudden , Electrophysiologic Techniques, Cardiac/methods , Electrophysiologic Techniques, CardiacABSTRACT
Visando avaliar o intervalo QTc e sua relação com variáveis clínicas, laboratoriais e com suscetibilidade da LDL à oxidação in vitro em pacientes com DM1, estudamos 40 diabéticos e 33 não diabéticos com idades de 24,83 ± 10,21 e 23,51 ± 7,28 anos, respectivamente, pareados por sexo, idade e índice de massa corporal (IMC). Avaliamos controle metabólico, apolipoproteínas A e B, coeficiente de oxidação da LDL por espectrofotometria e eletrocardiograma (ECG). O intervalo QTc foi calculado pela fórmula de Bazett. Não houve diferença no QTc entre os grupos dos DM1 e dos não diabéticos (394,43 ± 19,98 ms vs. 401,31 ± 17,83 ms; p = 0,2065). Cinco diabéticos apresentavam QTc aumentado (396,76 ± 14,63 ms vs. 429,75 ± 1,89 ms; p < 0,001) e menores níveis de apolipoproteína A que os demais diabéticos (74,60 ± 25,42 mg/dL vs. 113,64 ± 29,79 mg/dL; p = 0,011). Na amostra total, houve correlação entre QTc e IMC (rho = -0,288; p = 0,045), glicemia pós-prandial (rho = 0,357; p = 0,016) e coeficiente de oxidação 3 h (Cox3h) (r = -0,293; p = 0,039). Nos diabéticos, encontramos correlação entre QTc e triglicerídeos (rho = -0,420; p = 0,023) e Cox3h (r = -0,427; p = 0,021). Embora não tenhamos encontrado diferença entre o QTc dos diabéticos e não diabéticos estudados, houve correlação com marcadores de risco para a doença aterosclerótica. Entretanto, ainda são necessários mais estudos para estabelecer o real valor preditivo do QTc para esta doença nos pacientes com DM1.
To evaluate the QTc interval and its relation with clinical, laboratorial variables and LDL susceptibility to in vitro oxidation in patients with type 1 DM, we studied 40 diabetics and 33 non diabetics with 24.83 ± 10.21 and 23.51 ± 7.28 years old, respectively matched by sex, age and body mass index (BMI). We evaluated metabolic control, A and B apolipoproteins, LDL oxidation coefficient for spectrophotometry and electrocardiogram (ECG). Interval QTc was calculated by the Bazetts formula. There was no difference in QTc between diabetic and non diabetic groups (394.43 ± 19.98 ms versus 401.31 ± 17.83 ms; p = 0.2065). Five diabetics showed increased QTc (396.76 ± 14.63 ms versus 429.75 ± 1.89 ms; p < 0.001) and lesser A apolipoprotein levels than rest of diabetic group (74.60 ± 25.42 mg/dL versus 113.64 ± 29.79 mg/dL; p = 0,011). In pooled sample, there was correlation between QTc and BMI (rho = -0.288; p = 0.045), pot-prandial glycemia (rho = 0.357; p = 0.016) and 3 h oxidation coefficient (OxC3h) (r = -0.293; p = 0.039). In diabetics, there was correlation between QTc and triglycerides (rho = -0.420; p = 0.023) and OxC3h (r = -0.427; p = 0.021). Although there was no difference between QTc of diabetics and the non diabetics subjects studied, there was correlation with risk factors for the atherosclerotic disease. Further studies are necessary to establish the real predictive value of QTc for this type of disease in the patients with type 1 DM.
Subject(s)
Adult , Female , Humans , Male , Atherosclerosis/etiology , Diabetes Mellitus, Type 1/metabolism , Lipoproteins, LDL/metabolism , Long QT Syndrome/metabolism , Apolipoproteins A/blood , Apolipoproteins B/blood , Body Mass Index , Biomarkers/blood , Case-Control Studies , Diabetes Mellitus, Type 1/complications , Long QT Syndrome/complications , Oxidation-Reduction , Risk Factors , Statistics, Nonparametric , Triglycerides/bloodABSTRACT
Objetivo: Definir critérios eletrocardiográficos preditores de eventos cardíacos (síncope ou morte súbita) em portadores da síndrome do QT longo congênito (SQTLc). Métodos: Foram avaliados 11 portadores de SQTLc. Os critérios de inclusão foram: alta ou intermediaria probabilidade para SQTLc. Os critérios de inclusão foram: baixa probabilidade para QTLc e uso de drogas que prolongassem o intervalo QT. As seguintes variáveis foram analisadas: frequência cardíaca basal, intevalo QT corrigido (QTc), dispersão do QT e presença de alterações da repolarização ventricular. Esses parâmetros foram obtidos a partir de ECG basal realizado no momento do diagnóstico . O período de acompanhamento médio foi de 2,2 anos. Foi utilizado o teste do qui-quadrado para análise estatística. Resultados: A idade média ao diagnóstico foi de 24 anos e 82 por cento eram do sexo feminino. Oito pacientes (73 por cento) apresentavam cíncope e 1 paciente (9,9 por cento) apresentava história de morte súbita abortada. Apenas 1 pacientes apresentava cardiopatia estrutural associada )defeito do septo AV-forma total). Os pacientes foram estratificados em dois grupos. Grupo I - em eventos cardíacos, e Grupo II - sem eventos cardíacos....
Subject(s)
Humans , Male , Female , Adult , Death, Sudden/etiology , Syncope/complications , Syncope/mortality , Long QT Syndrome/complications , Electrocardiography, Ambulatory/methods , Electrocardiography, AmbulatoryABSTRACT
Long QT Syndrome (LQTS) is a cardiac channelopathy characterized by prolonged ventricular repolarization and increased risk to sudden death secondary to ventricular dysrrhythmias. Was the first cardiac channelopathy described and is probably the best understood. After a decade of the sentinel identification of ion channel mutation in LQTS, genotype-phenotype correlations have been developed along with important improvement in risk stratification and genetic guided-treatment. Genetic screening has shown that LQTS is more frequent than expected and interestingly, ethnic specific polymorphism conferring increased susceptibility to drug induced QT prolongation and torsades de pointes have been identified. A better understanding of ventricular arrhythmias as an adverse effect of ion channel binding drugs, allow the development of more safety formulas and better control of this public health problem. Progress in understanding the molecular basis of LQTS has been remarkable; eight different genes have been identified, however still 25% of patients remain genotype-negative. This article is an overview of the main LQTS knowledge developed during the last years.
El síndrome de QT largo (SQTL) es una canalopatía que genera grave alteración en la repolarización ventricular predispone a arritmias malignas y muerte súbita. Fue la primera canalopatía arritmogénica descrita y quizá la mejor entendida hasta ahora. Transcurrida ya más de una década de la identificación de la primera mutación asociada al SQTL, se ha hecho evidente que este trastorno es mucho más frecuente de lo que inicialmente se pensaba; los avances en el conocimiento de la fisiopatología molecular de esta enfermedad han permitido hacer una correlación genotipo-fenotipo, optimizando el tratamiento y permitiendo estratificar el riesgo en forma precisa. Se ha logrado entender con mayor detalle los efectos adversos de distintas drogas que interactúan con los canales iónicos, permitiendo así generar fármacos más seguros y, en su defecto, monitorizar de cerca aquellos que a pesar de tener este efecto adverso, es necesaria su administración. Los avances son importantes pero no todo está dicho, 25% de los casos no tienen mutaciones en los genes descritos hasta la fecha, por lo que el SQTL continúa siendo motivo de investigación. El presente artículo constituye un resumen de los principales conceptos desarrollados en los últimos diez años que han sido cruciales en el manejo de esta enfermedad.