RESUMO
The effects of digoxin on systolic and diastolic time intervals were studied in 25 children and infants the majority of whom had congenital heart disease by M mode echocardiography. The recordings were performed before and after the administration of digoxin. Serum digoxin levels were measured to confirm therapeutic dosage. After digoxin, the right and left ventricular pre-ejection periods, the duration of the corrected electromechanical systole and the Weissler indices decreased, and the isovolumic relaxation periods increased. The ventricular ejection times were unchanged except for the corrected right ventricular ejection time which was only slightly decreased. Our results concerning left ventricular systolic time intervals are in agreement with other studies in children. As no other studies of the effects of digoxin on the right ventricular systolic time intervals, or of the right and left isovolumic relaxation time are available, confirmatory studies are required. The decrease in the right and left pre-ejection periods, electromechanical systole and the Weissler indices, is interpreted as being related to the positive inotropic effect of digoxin whilst the increase in isovolumic relaxation reflects only a decrease in preload. This study allows a better understanding of the effects of digoxin on the different phases of the cardiac cycle and a better appreciation of its action potential.
Assuntos
Diástole/efeitos dos fármacos , Digoxina , Ecocardiografia , Contração Miocárdica/efeitos dos fármacos , Sístole/efeitos dos fármacos , Feminino , Cardiopatias Congênitas/diagnóstico , Humanos , Lactente , Masculino , Volume Sistólico/efeitos dos fármacos , Fatores de TempoRESUMO
The efficacy and safety of oral cibenzoline were evaluated in 42 patients aged 67 +/- 7 (55-80) and with recurrent symptomatic atrial fibrillation for at least a year and for which at least one previous anti-arrhythmic agent had been stopped for inefficacy or intolerance. Cibenzoline was administered for 6 months at the dose of 260 to 390 mg per day in patients aged under 70, with the possibility of reducing this dose in those aged over 70. Clinical, electrocardiographic and 24-hour Holter evaluation took place at inclusion and after 3 and 6 months' treatment or at the time of trial termination for documented recurrence (atrial arrhythmia persisting for 60 seconds or more). The mean duration of atrial fibrillation was 5.6 +/- 5 years (1-26). It was related to ischemic (22%), valvular (17%), hypertensive (17%), hypertrophic (7%) or dilated (7%) heart disease. No etiology was found in 45% of cases. All patients had taken at least one anti-arrhythmic agent in the past (mean of 2 drugs, range 1 to 6). All patients were symptomatic, the commonest symptoms being palpitations (82%), chest pain (28%), feelings of vertigo (11%) or episodes of acute dyspnea (9%). Thirteen patients (31%) had a documented recurrence (> 60 seconds) during the six months of the trial. Recurrence occurred during the first months of treatment in the majority of patients (11 out of 13). The number of symptomatic patients decreased considerably during treatment with cibenzoline, with the disappearance of palpitations in 83% of cases.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Antiarrítmicos/uso terapêutico , Fibrilação Atrial/prevenção & controle , Imidazóis/uso terapêutico , Administração Oral , Idoso , Idoso de 80 Anos ou mais , Antiarrítmicos/administração & dosagem , Antiarrítmicos/efeitos adversos , Eletrocardiografia , Eletrocardiografia Ambulatorial , Feminino , Humanos , Imidazóis/administração & dosagem , Imidazóis/efeitos adversos , Masculino , Pessoa de Meia-Idade , RecidivaRESUMO
Cibenzoline is a Vaughan-Williams class I anti-arrhythmic with properties intermediate between subclasses IA and IC which limit the incidence of proarrhythmic effects. These specific properties of the drug facilitate the prescription of cibenzoline in cardiology, particularly for the prevention of recurrent atrial arrhythmia: fibrillation, flutter, atrial tachycardia. This study demonstrates that cibenzoline is effective in these indications, since only 23% of the patients had relapsed after 6 months. This efficacy, combined with the good tolerance of the treatment, makes it possible to recommend the prescription of cibenzoline as a first-line treatment for the prevention of atrial arrhythmia. It represents an effective and safe option.