RESUMO
The effects of methylprednisolone (50 mg.kg-1) on the incidence of ventricular tachycardia and fibrillation and on ventricular fibrillation threshold were studied during acute coronary occlusion in anaesthetised dogs. Ventricular tachycardia and/or ventricular fibrillation occurred in 11 of the 16 animals (69%) both before and after methylprednisolone pretreatment. The mean ventricular fibrillation threshold of 10 dogs was 10.1 +/- 1.8 mA before methylprednisolone and it increased slightly to 13.3 +/- 2.3 mA after the drug. This difference was not statistically significant (P greater than 0.2).
Assuntos
Arritmias Cardíacas/tratamento farmacológico , Doença das Coronárias/tratamento farmacológico , Metilprednisolona/uso terapêutico , Animais , Cães , Metilprednisolona/administração & dosagem , Taquicardia/tratamento farmacológico , Fibrilação Ventricular/tratamento farmacológicoAssuntos
Eletrocardiografia , Taquicardia/fisiopatologia , Animais , Morte Súbita , Cães , Ventrículos do Coração/fisiopatologia , Humanos , Infarto do Miocárdio/complicações , Infarto do Miocárdio/mortalidade , Infarto do Miocárdio/fisiopatologia , Fibrilação Ventricular/complicações , Fibrilação Ventricular/fisiopatologiaAssuntos
Doença das Coronárias/fisiopatologia , Vasos Coronários/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Procainamida/efeitos adversos , Fibrilação Ventricular/induzido quimicamente , Animais , Cães , Eletrocardiografia , Ventrículos do Coração/fisiopatologia , Fibrilação Ventricular/diagnósticoAssuntos
Arritmias Cardíacas/fisiopatologia , Morte Súbita , Modelos Animais de Doenças , Coração/fisiopatologia , Fibrilação Ventricular/fisiopatologia , Angiocardiografia , Animais , Aorta Torácica/patologia , Arritmias Cardíacas/patologia , Autopsia , Angiografia Coronária , Vasos Coronários/patologia , Dieta Aterogênica , Eletrocardiografia , Coração/efeitos dos fármacos , Coração/efeitos da radiação , Sistema de Condução Cardíaco/fisiopatologia , Lidocaína/farmacologia , Pulmão/patologia , Masculino , Miocárdio/patologia , Propiltiouracila/farmacologia , Efeitos da Radiação , Suínos , Fibrilação Ventricular/patologiaAssuntos
Proteínas Sanguíneas , Viroses/sangue , Adolescente , Adulto , Eletroforese das Proteínas Sanguíneas , Criança , Pré-Escolar , Humanos , Lactente , Pessoa de Meia-IdadeRESUMO
Procainamide is known to depress conduction through the A-V node, and this property may facilitate the development of ventricular reciprocal beats or echoes. The occurrence of ventricular reciprocal beats was studied in 20 open-chest dogs before and after the administration of procainamide. While the ventricle was paced by basic stimuli, early ventricular premature beats were introduced at various coupling intervals to induce ventricular echoes. When ventricular echoes could be induced in a given heart, there was a continuous range of coupling intervals (or echo zone) within which ventricular echoes occurred. In the control state, no echo occurred in eight dogs and the echoes developed in 12 dogs with the mean echo zone of 38.3 msec. The effect of procainamide was studied at its therapeutic blood levels about 25 minutes after an intravenous injection of the drug in a dose of 10 mg. per kilogram. Of the first group of eight dogs, in which no echo occurred in the control state, four dogs developed ventricular echoes after the administration of procainamide with the mean echo zone of 29.3 msec. for the group. Of the second group of 12 dogs, in which ventricular echoes were induced in the control state, the administration of procainamide increased the echo zone in 10 dogs with the mean echo zone of 67.8 msec. for the group. Ventricular reciprocal beats were often sustained to produce short runs of supraventricular tachycardia in five dogs after the administration of procainamide. The results demonstrated a potentially deleterious effect of procainamide in facilitating the inducation of A-V nodal reciprocation by closely coupled ventricular premature beats.