ABSTRACT
INTRODUCTION: Parasympathetic dysfunction may play a role in the genesis of arrhythmias in Chagas disease. AIM: This study evaluates the acute effects of pyridostigmine (PYR), a reversible cholinesterase inhibitor, on the occurrence of arrhythmias in patients with Chagas cardiac disease. METHOD: Following a double-blind, randomized, placebo-controlled, cross-over protocol, 17 patients (age 50±2 years) with Chagas cardiac disease type B underwent 24-hour Holter recordings after oral administration of either pyridostigmine bromide (45 mg, 3 times/day) or placebo (PLA). RESULTS: Pyridostigmine reduced the 24-hours incidence (median [25%-75%]) of premature ventricular beats-PLA: 2998 (1920-4870), PYR: 2359 (940-3253), P=.044; ventricular couplets-PLA: 84 (15-159), PYR: 33 (6-94), P=.046. Although the total number of nonsustained ventricular tachycardia in the entire group was not different (P=.19) between PLA (1 [0-8]) and PYR (0 [0-4]), there were fewer episodes under PYR in 72% of the patients presenting this type of arrhythmia (P=.033). CONCLUSION: Acute administration of pyridostigmine reduced the incidence of nonsustained ventricular arrhythmias in patients with Chagas cardiac disease. Further studies that address the use of pyridostigmine by patients with Chagas cardiac disease under a more prolonged follow-up are warranted.
Subject(s)
Anti-Arrhythmia Agents/administration & dosage , Chagas Cardiomyopathy/drug therapy , Cholinesterase Inhibitors/administration & dosage , Heart Rate/drug effects , Pyridostigmine Bromide/administration & dosage , Tachycardia, Ventricular/prevention & control , Ventricular Premature Complexes/prevention & control , Administration, Oral , Anti-Arrhythmia Agents/adverse effects , Asymptomatic Diseases , Brazil , Chagas Cardiomyopathy/diagnosis , Chagas Cardiomyopathy/parasitology , Cholinesterase Inhibitors/adverse effects , Cross-Over Studies , Double-Blind Method , Drug Administration Schedule , Electrocardiography, Ambulatory , Female , Humans , Male , Middle Aged , Pyridostigmine Bromide/adverse effects , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/parasitology , Tachycardia, Ventricular/physiopathology , Time Factors , Treatment Outcome , Ventricular Premature Complexes/diagnosis , Ventricular Premature Complexes/parasitology , Ventricular Premature Complexes/physiopathologyABSTRACT
FUNDAMENTO: As extrassístoles ventriculares e supraventriculares (EV e ESSV) são frequentes e muitas vezes sintomáticas. O íon magnésio (Mg) desempenha um papel importante na fisiologia do potencial de ação transmembrana celular e do ritmo cardíaco. OBJETIVO: Avaliar se a administração do pidolato de magnésio (PMg) em pacientes com EV e ESSV tem desempenho superior ao uso do placebo (P) na melhora dos sintomas e densidade das extrassístoles (DES). MÉTODOS: Estudo duplo-cego, randomizado, com 60 pacientes sintomáticos consecutivos, com mais de 240/EV ou ESSV ao Holter de 24 horas e selecionados para receber P ou PMg. Para avaliar a melhora da sintomatologia, foi feito um questionário categórico e específico de sintomas relacionados às extrassístoles. Após o tratamento, foi considerada significante uma redução de mais de 70% na DES por hora. A dose do PMg foi de 3,0 g/dia por 30 dias, equivalente a 260 mg do elemento Mg. Nenhum paciente tinha cardiopatia estrutural ou insuficiência renal. RESULTADOS: Dos 60 pacientes estudados, 33 eram do sexo feminino (55%). A faixa etária variou de 16 a 70 anos. No grupo PMg, 76,6% dos pacientes tiveram redução maior que 70%, 10% deles maior que 50% e somente 13,4% tiveram redução menor que 50% na DES. No grupo P, 40% dos pacientes tiveram melhora de apenas 30% na frequência de extrassístoles (p < 0,001). A melhora dos sintomas foi alcançada em 93,3% dos pacientes do grupo PMg, comparada com somente 16,7% do grupo P (p < 0,001). CONCLUSÃO: A suplementação de Mg via oral reduziu a DES, resultando em melhora dos sintomas.
BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE:We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260mg of Mg element. None of the patients had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the premature complexes frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.
Subject(s)
Adolescent , Adult , Aged , Female , Humans , Middle Aged , Young Adult , Atrial Premature Complexes/drug therapy , Pyrrolidonecarboxylic Acid/administration & dosage , Ventricular Premature Complexes/drug therapy , Atrial Premature Complexes/prevention & control , Double-Blind Method , Placebo Effect , Statistics, Nonparametric , Time Factors , Treatment Outcome , Ventricular Premature Complexes/prevention & controlABSTRACT
BACKGROUND: Premature ventricular and supraventricular complexes (PVC and PsVC) are frequent and often symptomatic. The magnesium (Mg) ion plays a role in the physiology of cell membranes and cardiac rhythm. OBJECTIVE: We evaluated whether the administration of Mg Pidolate (MgP) in patients with PVC and PsVC is superior to placebo (P) in improving symptoms and arrhythmia frequency. METHODS: Randomized double-blind study with 60 consecutive symptomatic patients with more than 240 PVC or PsVC on 24-hour Holter monitoring who were selected to receive placebo (P) or MgP. To evaluate symptom improvement, a categorical and a specific questionnaire for symptoms related to PVC and PsVC was made. Improvement in premature complex density (PCD) per hour was considered significant if percentage reduction was >70% after treatment. The dose of MgP was 3.0 g/day for 30 days, equivalent to 260 mg of Mg element. Any patient had structural heart disease or renal failure. RESULTS: Of the 60 patients, 33 were female (55%). Ages ranged from 16 to 70 years old. In the MgP group, 76.6% of patients had a PCD reduction >70%, 10% of them >50% and only 13.4% <50%. In the P group, 40% showed slight improvement, <30%, in the PC frequency (p < 0.001). Symptom improvement was achieved in 93.3% of patients in the MgP group, compared with only 16.7% in the P group (p < 0.001). CONCLUSION: Oral Mg supplementation decreases PCD, resulting in symptom improvement.
Subject(s)
Atrial Premature Complexes/drug therapy , Pyrrolidonecarboxylic Acid/administration & dosage , Ventricular Premature Complexes/drug therapy , Adolescent , Adult , Aged , Atrial Premature Complexes/prevention & control , Double-Blind Method , Female , Humans , Male , Middle Aged , Placebo Effect , Statistics, Nonparametric , Time Factors , Treatment Outcome , Ventricular Premature Complexes/prevention & control , Young AdultABSTRACT
Iniciar o tratamento com antiarrítmicos em portadores de extra-sístoles ventriculares pode ser uma questäo bem difícil, algumas vezes polêmica, dependendo das circunstâncias. Os batimentos ectópicos ventriculares prematuros são a manifestaçäo mais comum dos distúrbios do ritmo cardíaco, surgindo freqüentemente em pessoas sadias. Esta decisäo deve-se basear na presença de sintomas limitantes, alteraçöes estruturais cardíacas e comprometimento da funçäo contrátil ventricular. Os mecanismos eletrofisiológicos responsáveis pelo aparecimento das contraçöes ventriculares precoces säo: parasistolia, reentrada e atividade deflagrada. Cada um deles apresenta características definidas, tanto na sua demonstraçäo experimental, como na sua exteriorizaçäo eletrocardigráfica. A investigaçäo completa do paciente com extra-sístoles ventriculares compreende: história clínica, exame físico, eletrocardiograma (em repouso, ambulatorial e durante esforço), ecocardiograma, radiosiótopos, ressonância magnética e eletrocardiografia de alta resoluçäo. Raramente, utiliza-se: cineangiocoronariografia, cineventriculografia e estudo eletrofsiológico intracardíaco. Seräo medicados com antiarrítmicos somente os casos com lesäo cardíaca evidente. Incluem-se nesta situaçäo: determinadas cardiopatias congênitas, valvopatias, miocardiopatias e insuficiência coronária (aguda ou crônica). Existindo grande risco de morte súbita e sendo a arritmia cardíaca refratária, há necessidade do emprego de métodos terapêuticos näo farmacológicos. Os principais medicamentos antiarrítmicos recomendados säo: amiodarona, propafenona, sotalol, quinidina, procainamida, mexiletine, disopiramida, flecainida, verapamil e difenil-hidantoína. A lidocaína é a única medicaçäo exclusivamente de uso parenteral. O emprego destes fármacos pode provocar o aparecimento de novos distúrbios do ritmo ou agravamento das alteraçöes pré-existentes, principalmente quando a funçäo ventricular encontra-se gravemente comprometida. Portanto, deve-se prescrever apropriadamente os antiarrítmicos, identificar as condiçöes clínicas do seu aparecimento e evitar, tanto quanto possível, associaçöes de medicamentos.