antiarrhytmics

Overall, pain is one of the most common symptoms associated with cancer and often produces greater anticipatory distress than other features of the disease. Drug selection depends on the intensity of pain rather than on the specific pathophysiology. Mild to moderate pain can often be treated effectively by so-called "weak" opioids. Non-opioid analgesics, like acetyl-salicylic acid or paracetamol can be added according to the "analgesic ladder" proposed by the World Health Organization (WHO). Opioids should be given on a fixed time schedule thereby, preventing pain from recurring...

Experimental ventricular tachycardias (VT) were provoked in dog hearts with minute crystals of aconitine introduced into the periphery of an infarcted area, produced by intramural injection of 1-1.5 ml of phenol. The response of these tachycardias to verapamil was studied. Leads II, aVL, intraventricular right and left unipolar records, as well as one on the superior vena cava were registered under control conditions, with VT and after the injection of the antiarrhythmic agent. This injection was infused into superior vena cava over 15-20 minutes...

The synthesis of nine compounds belonging to the group of aryloxyaminopropanols with carbamate substitutions of the aromatic ring is described and pharmacologically evaluated. The results suggest that an addition of N-phenyl-piperazine derivatives to the main basic moiety can exert a positive influence on their beta-adrenolytic, antiarrhytmic or antihypertensive activity.

Effect of various oxygen free radical generating systems and an oxidant H2O2 on brain endoplasmic reticulum (ER) membrane fluidity was examined using fluorescent membrane probe 1,6-diphenyl-1,3,5-hexatriene, DPH. The relative potency of free radical generating systems to decrease membrane fluidity increased in this order: FeCl3-EDTA, FeSO4-EDTA, FeSO4-EDTA/hydrogen peroxide. Potency to decrease membrane fluidity correlated well with these systems' potencies to induce lipid peroxidation, as detected by conjugated diene formation...

Smooth and interrupted curves of AV conduction, generated with an atrial extrastimulus technique, are seen in man, suggesting the involvement of two physiological AV pathways named "alpha" and "beta" and leading to a final common pathway (FCP). In view of this knowledge, the effects of some representative antiarrhytmic agents (Atropine, Verapamil, Ajmaline) were studied in eight patients in order to elucidate the physiological role of the various components of AV junction. Verapamil decreased conduction velocity of both "alpha" and "beta" pathways and increased their refractoriness; Atropine decreased "alpha" and "beta" pathways' refractory periods and increased their conduction velocity; further studies are required to clarify the effects of Ajmaline on AV conduction...

Ventricular arrhythmias due to myocardial infarct were produced in 14 dogs, and the antiarrhytmic effects of quinidine (Qd), lidocaine (Lid), aprindine (Apr), and dl-propranolol (dl-Prop) were investigated. While recording the blood pressure and lead II ECG, a coronary cannula was inserted into a coronary orifice via the left carotid artery and a glass bead (diameter, 1.5 mm) was flushed into the left coronary artery. Beads were found at the descending branches in 12 and circumflex branches in 2 out of 14 gods, at autopsy...

In order to relate the cardiac antiarrhytmic properties of magnesium chloride (MgCl2) to its electrophysiological effects, a comparison of its actions on three different models of automaticity of the isolated Purkinje fibers of the dog, has been carried out. The spontaneous activity of the Purkinje fibers perfused with Tyrode's solution containing 2.7 mM KC1 was gradually reduced as MgC12 concentration was increased from 3 to 9 mM/1. The automaticity induced adding barium chloride (BaC12) to the perfusion solution was suppressed increasing the concentration of MgC12 in the Tyrode's solution up to 5 mM/1...

A 52 year old patient with no previous medical history had an attack of ventricular tachycardia, the configuration of which showed left sided delay. Electrical reduction was followed by multiple recurrences. There were ST-T wave changes over the right precordium on the basal ECG. The hydro-electrolytic equilibrium was normal. Coronary angiography and selective left ventricular cineangiography were also normal. Right angiocardiography showed an aneurysmal deformation of the pulmonary infundibulum. The recurrence of attacks over a two year period led to several hospital admissions, demonstrating the failure of antiarrhytmic therapy...

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Longitudinal monitoring of the electrocardiogram by Holter's method is indicated in particular for the diagnosis of intermittent dysrhythmia which may be related to the symptom of syncope in elderly patients. Transient dysrhythmia with subsequent cerebral ischemia may be the cause of altered consciousness, vertige, presyncopes, or true syncopes. Transient dysrhythmias may be therefore considered after elimination of other causes of syncopes as their aetiology, in particular in elderly patients and old age groups where organic heart disease is already present...

Effects of a new antiarrhytmic compound KC 3791 on sodium (INa) and potassium (IK) currents were studied in frog myelinated nerve fibres under voltage clamp conditions. When applied externally to the node of Ranvier, KC 3791 (KC) at concentrations of 10(-5)-10(-4) mol.l-1 produced both tonic and cumulative (use-dependent) inhibition of INa. An analysis of the frequency-, voltage- and time dependence of cumulative block by KC suggested that this block resulted from a voltage-dependent interaction of the drug with open Na channels...

Bonnecor is excreted in rats both via urine (3/4) and bile (1/4). It was the aim of this study to find out suitable methods for detoxication of a poisoning with this antiarrhytmic drug. In vivo methods intended to enhance the renal excretion of Bonnecor (forced diuresis, changes in urinary pH-values, peritoneal dialysis) are not qualified for therapeutically relevant increase of Bonnecor elimination. Relating to this Bonnecor is quite comparable with other antiarrhythmic drugs or dibenzazepine derivatives. The hemoperfusion can be recommended for the therapy of a Bonnecor overdosage as a propping up of symptomatic methods of intensive care, which are precendentally indicated...

The action of two antiarrhytmic drugs, moracizine (MOR, CAS 31883-05-3) and ethacizine (ETHA, CAS 33414-33-4) on receptors of potential-operated CA-channels has been investigated. ETHA binding to verapamil receptors was more effective than that of MOR (IC50 = 0.53 +/- 0.08 mumol/l, respectively). The Hill coefficient for ETHA binding was similar to that of verapamil (0.64 +/- 0.09 and 0.60 +/- 0.10, respectively). Interaction of ETHA and MOR with dihydropyridine receptors in concentrations up to 10 mumol/l was similar that of verapamil, however, MOR was less potent...

With the help of an analysis of the world literature pharmacological, pharmacokinetic and electrophysiological properties as well as the possibilities of the clinico-therapeutic use of Bretylium tosylat are demonstrated. The pharmacon is of increasing interest as antiarrhytmic, especially in the commandment of otherwise therapy-refractory ventricular disturbances of rhythm. A positively inotropic effect is proved. More severe side effects, such as arterial hypotension and increase of the pulmonary vascular resistance have an objection to routine application...

In rabbits with experimental myocardial infarction (EMI) complicated by arrhthmias the antiarrhythmic action of neocompensan (haemodesum) was ascertained for the first time. In the acute period of EMI no electrolytes shifts in the blood serum of the animals were disclosed and this justified the antiarrhythmis effect of neocompensan, occurring during the first 24 hours of the experiment, to be attributed to the influence of polyvinylpyrrolidine. Besides, the drug produced in rabbits with EMI deceleration of the total blood coagulation...

With the purpose of estimating quantitative differences between disopyramide and quinidine two experimental series were designed. In order to establish the atropinic potency of both drugs, pA2 values were determined in rabbits right atria, using acetylcholine as agonist. The capacity to prevent ventricular fibrillation in albino mice subjected to chloroform apnea was also tested using various doses of the drugs. An effective median dose (ED50) to each of the drugs was calculated and the relative antiarrhythmic potency was compared...

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3 (3'-Morpholino-2'-hydroxypropoxy)--7--9 as well as 3 (3'-morpholino-2'-hydroxypropyloamino) 14 -- 16 derivatives of 1-methyl and 1-phenyl pyrazo-[3,4-b]-pyridines were prepared and screened for expected circulatory activity. Compounds 7, 11--14, 20 mg/kg, produced hypotension in cats; Compounds 7 and 14, 50--80 mg/kg, had antiarrhytmic action in BaCl2 -- induced arrhytmic in the rabbit.

Effects of antiarrhythmic drugs upon the threshold delivered energy (TDE) and threshold peak current (TPC) for electrical ventricular defibrillation by damped sinusoidal shocks were investigated in 25 pentobarbital-anesthetized dogs. TDE and TPC were increased by the three antiarrhytmic drugs tested. Bolus injections produced a transient rise and continuous infusions produced a steady rise in difibrillation threshold. The maximal percent elevations in mean defibrillation threshold during the 60 minutes after intravenous drug treatment in groups of n = 5 dogs were: (formula: see text)...