Cardiotonic activity of aqueous extract of heartwood of Pterocarpus marsupium.

The present study was undertaken to evaluate cardiotonic activity of aqueous extract of heartwood of P. marsupium. This plant species contains 5,7,2-4 tetrahydroxy isoflavone 6-6 glucoside which are potent antioxidant and are believed to prevent cardiovascular diseases. Cardiotonic effect of aqueous extract of heartwood of P. marsupium was studied by using isolated frog heart perfusion technique (IFHP). Calcium free Ringer solution was used as vehicle for administration of aqueous extract of P. marsupium as a test extract and digoxin as a standard. A significant increase in height of force of contraction (positive inotropic effect) and decrease in heart rate (negative chronotropic effect) at a very low concentration (0.25 mg/ml) was observed with test extract as compared to the same dose of a standard digoxin. The present results indicated that a significant increase in height of force of contraction with decrease in heart rate was observed as the dose of test extract increased. The test extract produced cardiac arrest at 4 mg/ml, a higher concentration, as compared to standard, digoxin (0.5 mg/ml). Compared to digoxin, a drug with narrow therapeutic window, P. marsupium showed wide therapeutic window.

Protective effect of digoxin on impaired chronotropic responsiveness to adrenergic stimulation in cholestatic rats

Decreased cardiac responsiveness to adrenergic stimulation has been observed in cholestatic liver disease, but the cause remains unclear. Previous reports have suggested that nitric oxide overproduction might have a role in cholestasis-induced bradycardia via inhibition of L-type calcium channels. In the present study, the digoxin has been used to increase cardiac Ca2+ transient in male Sprague-Dawley rats with obstructive cholestasis and the chronotropic responsiveness to adrenergic stimulation was evaluated. Cholestasis was induced by surgical ligation of the bile duct under general anesthesia and sham-operated animals were considered as control. The animals were divided into two groups, which received either digoxin [10, 20 micro g/kg/day] or saline. One week after the operation, spontaneously beating atria were isolated and chronotropic responses to epinephrine were evaluated in a standard oxygenated organ bath. The basal spontaneous beating rate of the atria in the cholestatic animals was not significantly different from that of sham-operated rats in vitro. Meanwhile, cholestasis induced a significant decrease in chronotropic effect of epinephrine. This effect was corrected by daily administration of digoxin [20 micro g/kg/day]. The results also showed that plasma alkaline phosphatase activity was increased by bile-duct ligation, and digoxin treatment had no effect in the elevation of this marker of liver damage. The protective effect of digoxin on impaired chronotropic responsiveness to adrenergic stimulation in cholestatic rats might be related to increase of Ca2+ transient. However, further studies are necessary to confirm the molecular basis of this effect

Effect of two cardiac glycosides, digitoxin and digoxin on blood lipids.

Two cardiac glycosides, namely digitoxin and digoxin when treated with goat blood, were found to alter the lipid constitution as measured by their phosphorus content, fatty acid composition and malonaldehyde content. There was significant increase in the poly-unsaturated fatty acids (PUFA) and malonaldehyde contents in blood treated with these drugs. Possible correlation between the lipophilicity of the drugs and their biological activity is discussed.

Comparación de digoxina y atenolol en fibrilación auricular crónica / Comparison between digoxin and atenolol in chronic atrial fibrillation

The benefits of digoxin in patients with atrial fibrillation may be reduced due to its limited effect on atrioventricular conduction. The aim of this work was to compare digoxin and etanolol on functional class, resting and exercise heart rate and exercise capacity in patients with atrial fibrillation. Thirteen subjects with this condition, normal echocardiographic left ventricular function and size, a resting heart rate less than 80 beats/min and with no contraindication for beta blocker or digoxin use, were studied. Patients were randomly assigned to receive initially digoxin 0.25 mg. o.d. or atenolol 100 mg o.d. in a double blind fashion. The doses were sdjusted to obtain a heart rate between 60 and 80 beats-min at the end of the first week of treatment. After 2 weeks of treatment, outcomes were assessed, patients were left without treatment for one week and crossed over to the other drug after that. Resting heart rates achieved with digoxin and atenolol were similar (67ñ11 and 65ñ23 beats/min respectively). However, maximal exercise heart rates and maximal exercise time were higher during digoxin treatment (166ñ23 vs 135ñ27 beats/min and 9.95ñ1.68 vs 8.5ñ2 min respectively). NYHA functional class deteriorated in 3 patients receiving atenolol. We conclude that atenolol achieves a better control of heart rate during exercise but also reduces maximal exercise capacity

La digoxina es efectiva en el tratamiento de pacientes con insuficiencia cardíaca y ritmo sinusal / Digoxin is effectiveness in the treatment of cardiac failure and sinus rhythm patients

Due to differences in treatment effect in studies on the effectiveness of digoxin in patients with congestive heart failure in sinus rhythm, a cross-over placebo-controlled randomized double blind clinical trial was performed. Thirty one patients, without previous treatment with digoxin, in New York Heart Association (NYHA) functional class II to IV, with a dilated left ventricle and/or ventricular systolic dysfunction were included. Patients received digoxin, adjusted for blood levels, or placebo, during an 8 week period, prior to crossing over to the other treatment for another 8 weeks. The order of tretments was randomly allocated. Outcome measurement were performed at the end of each 8 week period. Digoxin, compared with placebo, improved NYHA class, 6,9 por ciento vs 41.4 por ciento (p=0.013) and increased the treadmill exercise time, 406 ñ 204 s vs 484 ñ 185 s (p=0.003). During the digoxin treatment the left ventricular and systolic diameter was reduced from 52.9 ñ 8.9 to 50.1 ñ 9.7 mm (p=0.009). No significant difference was observed in the left ventricular end diastolic diameter (LVED) of the left ventricle and in a estimation of quality of life. In conclusion, digoxin treatment produced a significant improvement in functional capacity, exercise time and left ventricular performance

Emergências cardiovasculares. Parte 1: intoxicaçäo digitálica / Cardiovascular emergencies. Part 1: Digitalis intoxication

Os autores mostram a relevância da intoxicaçäo digitálica dentre as emergências cardiológicas. Realçam a utilidade dos anticorpos monoclonais na intoxicaçäo suicida e o uso do sulfato de magnésio

Supraventricular tachyarrthmias efficacy of verapamil

verapamil is the drug most widely used in the management of supraventricular tachyarrhythias [SVT] in the absence of contraindications. Hypotention complicating SVT is not considered an absolute contraindication for the use of IV verapamil. The purpose of this study was to assess the efficacy of IV Verapamil in SVT. And its safety in the patients with arterial hypotension. The study was retrospective conducted in Salmaniya Medical Center, Accident and Emergency Department. Inclusion criteria were: SVT [defined as narrow complex tachycardia with regular R.R. interval and rate of 150 BPM or more, systolic blood pressure between 90 and 150mm/Hg. 60 consecutive cases were included, age range 27-70 years, female male = 46 14 i.e. ration 3 1. all patients with organic heart diseases, heart failure, thyroid disease or ECG abnormality rather than SVT. Were excluded from the study. Verapamil was administered in 58 patients. One patient converted spontaneously to NSR before treatment and one patient reverted with carotid massage. Carotid massage was tried as first line therapy in only 2 patients. Three patients did not respond to verapamil but reverted following digoxin IV efficacy of verapamil was 94.8% [55/58]. Hypotension following verapamil was not encountered in any patient. Hematological investigations were done in 59 patients [98.3%] and chest radiographs were done in 59 patients [98.3%]. These had no influence on the management and so were deemed unnecessary. 12 patients [20%] were admitted to rule out ischemic heart disease. The remaining was discharged from A/E within few hours

Frusemide--digitalis interaction on experimental model.

Interaction of frusemide and digitalis on frog heart has been studied. It was found that like digitalis, frusemide did not have any effect on normal heart, but restored the normal myocardial contraction of the hypodynamic frog heart. Frusemide induced cardiac arrest when administered during digoxin infusion. It is suggested that interaction of frusemide and digoxin has additive effect.

Use of electromagnetic counterpoise to measure cardiac force.

To quantify the drug induced changes in cardiac force the methods in vogue use springs and strain-gauge coils, which apply counterforce to oppose cardiac force and thus stop systolic excursion of the lever. The present report pertains to a new technique based on similar principle, utilising induced electromagnetic force as a means of counterpoising in study of contractility of isolated, frog heart. The technique monitered changes in contractility produced by small doses of adrenaline, digoxin, acetylcholine and CaCl2. The plots of estimated cardiac force (in V) against doses (log-units) of the drugs could be made to reveal dose response relation.