RESUMO
INTRODUCTION: Gly389Arg ß1 adrenergic receptor polymorphisms seem to exert an influence on the modulation of the adrenergic effect in several types of patients. This study aimed to determine the prevalence of Gly389Arg polymorphisms among patients with evidence of double nodal pathway and to correlate the electrophysiological properties with the different genotypes of the respective polymorphisms. METHODS: A cross-sectional, descriptive and analytical study was designed to assess 49 patients, with evidence of double nodal pathway, submitted to electrophysiological study. Genomic DNA was extracted from peripheral blood leukocytes and the genotypes of the Arg389Gly polymorphisms were identified in all individuals by PCR/RFLP (polymerase chain reaction/restriction fragment length polymorphism). RESULTS: The majority of patients were female and had supraventricular tachycardia (75.5%). The prevalence of Arg389Arg genotype was found in 32 patients (65.3%), Arg389Gly genotype in 16 patients (32.7%) and Gly389Gly genotype in 1 patient (2%). With respect to the induction of nodal reentrant tachycardia, it was possible to induce non-isoproterenol tachycardia in 32 patients (65.3%), of whom 24 had the Arg389Arg genotype and 8 the Arg389Gly and Gly389Gly genotype (p = 0.05). The resting heart rate of patients of the Arg389Arg genotype was 81 ± 18 bpm and the Arg389Gly and Gly389Gly genotype of 71 ± 9 bpm (p = 0.044). Body mass index (BMI) among patients with genotype Arg389Gly and Gly389Gly was 29.8 ± 7.1 and patients with the Arg389Arg genotype was 26.2 ± 4.6 (p = 0.034). CONCLUSION: The Arg389Arg genotype was more easily related to triggering arrhythmia, higher resting heart rate and lower BMI.
RESUMO
CONTEXT AND OBJECTIVE: Occurrences of asymptomatic atrial fibrillation (AF) are common. It is important to identify AF because it increases morbidity and mortality. 24-hour Holter has been used to detect paroxysmal AF (PAF). The objective of this study was to investigate the relationship between occurrence of PAF in 24-hour Holter and the symptoms of the population studied. DESIGN AND SETTING: Cross-sectional study conducted at a cardiology hospital. METHODS: 11,321 consecutive 24-hour Holter tests performed at a referral service were analyzed. Patients with pacemakers or with AF throughout the recording were excluded. RESULTS: There were 75 tests (0.67%) with PAF. The mean age was 67 ± 13 years and 45% were female. The heart rate (HR) over the 24 hours was a minimum of 45 ± 8 bpm, mean of 74 ± 17 bpm and maximum of 151 ± 32 bpm. Among the tests showing PAF, only 26% had symptoms. The only factor tested that showed a correlation with symptomatic AF was maximum HR (165 ± 34 versus 147 ± 30 bpm) (P = 0.03). Use of beta blockers had a protective effect against occurrence of PAF symptoms (odds ratio: 0.24, P = 0.031). CONCLUSIONS: PAF is a rare event in 24-hour Holter. The maximum HR during the 24 hours was the only factor correlated with symptomatic AF, and use of beta blockers had a protective effect against AF symptom occurrence. .
CONTEXTO E OBJETIVO: A ocorrência de fibrilação atrial (FA) assintomática é comum. A identificação da FA é importante e está associada com maior morbimortalidade. O Holter de 24 horas vem sendo utilizado para a detecção de FA paroxística (FAP). O objetivo desse estudo é investigar a relação entre a ocorrência de FAP no Holter de 24 horas e os sintomas na população estudada. TIPO DE ESTUDO E LOCAL: Estudo transversal realizado em um hospital de cardiologia. MÉTODOS: Análise de 11.321 exames consecutivos de Holter de 24 horas realizados em serviço de referência. Foram excluídos pacientes com marcapasso e aqueles com FA durante toda a gravação. RESULTADOS: Foram identificados 75 (0,67%) exames apresentando FAP. A idade média foi de 67 ± 13 anos e 45% eram do sexo feminino. A frequência cardíaca (FC) encontrada nas 24 horas foi mínima de 45 ± 8 bpm, média de 74 ± 17 bpm e máxima de 151 ± 32 bpm. Entre os exames apresentando FAP, apenas 26% apresentaram sintomas. O único fator testado que evidenciou correlação com FA sintomática foi a FC máxima (165 ± 34 versus 147 ± 30 bpm) (P = 0,03). O uso de betabloqueadores teve efeito protetor para ocorrência de sintomas na FA (odds ratio: 0.24, P = 0.031). CONCLUSÕES: A FAP é um evento raro em Holter de 24 horas. A FC máxima nas 24 horas foi o único fator relacionado com FA sintomática e o uso de betabloqueadores teve efeito protetor para ocorrência de sintomas na FA. .
Assuntos
Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Assintomáticas , Fibrilação Atrial/diagnóstico , Eletrocardiografia Ambulatorial/métodos , Frequência Cardíaca/fisiologia , Antagonistas Adrenérgicos beta/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/fisiopatologia , Brasil , Estudos TransversaisRESUMO
CONTEXT AND OBJECTIVE: Occurrences of asymptomatic atrial fibrillation (AF) are common. It is important to identify AF because it increases morbidity and mortality. 24-hour Holter has been used to detect paroxysmal AF (PAF). The objective of this study was to investigate the relationship between occurrence of PAF in 24-hour Holter and the symptoms of the population studied. DESIGN AND SETTING: Cross-sectional study conducted at a cardiology hospital. METHODS: 11,321 consecutive 24-hour Holter tests performed at a referral service were analyzed. Patients with pacemakers or with AF throughout the recording were excluded. RESULTS: There were 75 tests (0.67%) with PAF. The mean age was 67 ± 13 years and 45% were female. The heart rate (HR) over the 24 hours was a minimum of 45 ± 8 bpm, mean of 74 ± 17 bpm and maximum of 151 ± 32 bpm. Among the tests showing PAF, only 26% had symptoms. The only factor tested that showed a correlation with symptomatic AF was maximum HR (165 ± 34 versus 147 ± 30 bpm) (P = 0.03). Use of beta blockers had a protective effect against occurrence of PAF symptoms (odds ratio: 0.24, P = 0.031). CONCLUSIONS: PAF is a rare event in 24-hour Holter. The maximum HR during the 24 hours was the only factor correlated with symptomatic AF, and use of beta blockers had a protective effect against AF symptom occurrence.