RESUMO
Micturition syncope accounts for 8.39% of the total number of syncopes and is prevalent among men in the 50 and 60 year age groups. The cardiovascular vegetative nervous system is unaffected in patients with micturition syncope. Sixty-one percent of patients with micturition syncope also exhibit other kinds of syncope. These patients experience vasovagal reaction during the vegetative activation tests more often than patients exclusively with micturition syncope.
Assuntos
Doenças do Sistema Nervoso Autônomo/fisiopatologia , Hipóxia Encefálica/fisiopatologia , Síncope/fisiopatologia , Micção/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Sistema Nervoso Autônomo/fisiopatologia , Doenças do Sistema Nervoso Autônomo/diagnóstico , Pressão Sanguínea/fisiologia , Criança , Pré-Escolar , Eletrocardiografia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Hipóxia Encefálica/diagnóstico , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Manobra de Valsalva/fisiologiaRESUMO
The vagal cardiac activity was compared in two groups of patients with a history of syncope. Sixty-one patients (Group A) experienced vasovagal reactions induced by head-up tilt, 61 sex and age-matched patients (Group B) did not. No significant differences in vagal cardiac activity between two groups were found. Group A was further subdivided into two subgroups: A1 (14 patients) with stronger, and A2 (47 patients) with smaller cardioinhibition. Again, vagal cardiac activity was not different between two subgroups. Thus, the baseline vagal cardiac activity ('tone') seemed not to be helpful in predicting the susceptibility to vasovagal orthostatic syncope and in discriminating the patients with stronger cardioinhibition.
Assuntos
Coração/fisiopatologia , Síncope/fisiopatologia , Nervo Vago/fisiopatologia , Adulto , Pressão Sanguínea , Eletrocardiografia , Eletroencefalografia , Feminino , Coração/inervação , Coração/fisiologia , Frequência Cardíaca , Humanos , Masculino , Postura , Valores de Referência , Nervo Vago/fisiologia , Manobra de ValsalvaRESUMO
Head-up tilt to 70 degrees lasting for 30 min is a further useful test for studying syncope. In 26.69% of 109 consecutive out-patients referred for loss of consciousness, it induced vasodepressor and/or cardioinhibitory reactions. All symptomatic patients had similar EEG changes and blood pressure fall during symptoms: by contrast, ECG features, due to vagal activation, were different. The pathogenetic mechanism of vasovagal or vasodepressor syncope is an abrupt sympathetic cardiovascular inhibition with more or less marked vagal cardiac activation. This cardiovascular pattern is due to a cardiac reflex in orthostatic syncope or, probably, to a central activation in emotional fainting.
