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PubMed1988

[Effect of allapinin after a single intravenous administration to patients with chronic ventricular extrasystole].

Clinical assessment of a new antiarrhythmic drug, allapinin, was carried out in 42 patients with chronic ventricular extrasystoles. Single intravenous doses were effective where they exceeded 0.32 mg/kg. Doses above 0.42 mg/kg were regularly associated with side effects, such as dizziness or, less commonly, diplopia. The 0.39 mg/kg dose produced an antiarrhythmic effect in 61% of patients, whose PQ interval was lengthened by 23%, and the QRS complex, by 18%, while QTc duration remained unchanged. Heart rate and arterial blood pressure were virtually unchanged, either. The peak of antiarrhythmic effect fell to the second postadministration hour, and the effect persisted within an average of 7.6 hours. Therefore, allapinin appears to be a potent quinidine-like agent.

Aconitine↗
PubMed1988

[Evaluation of functional reserves of the myocardium in patients with heart defects on the basis of changes in systolic time intervals during post-extrasystolic contraction].

Changes in pre-ejection period (T) and ejection time (E) during the post-extrasystolic beat, as compared to regular sinus rhythm, as well as ratios thereof can be useful for the assessment of myocardial activity and reserve in patients with heart diseases. The potentiation index, proposed by the authors, i. e. the ratio between the difference between absolute delta E-delta T changes and the absolute change in Weisler's coefficient (delta T/E), has the highest value in this respect.

Adolescent↗
PubMed1988

Cardiac and side effects of prostaglandin F2 alpha in patients with extrasystoles.

In 17 patients with cardiac extrasystoles, prostaglandin (PG) F2a (= alpha) administered intravenously at consecutive infusion rates of 25 to 100 micrograms/min showed the following effects in a dose-dependent manner: prolongation of total electromechanical systole, pre-ejection period, and left ventricular ejection time, indicating a negative inotropic activity, increase in systolic and diastolic blood pressure, and incidence of side effects. An additional 2 patients were excluded from the uniform evaluation because the PGF2a dosage was changed owing to a clear antiarrhythmic action in one and serious side effects in the other. The results supplement clinical-pharmacological findings with PGF2a.

Anti-Arrhythmia Agents↗
PubMed1989

[Calcium metabolism and transmembrane potential of thrombocytes in patients with frequent ventricular extrasystole treated with anti-arrhythmia drugs].

The effect of antiarrhythmic drugs on platelet calcium metabolism in peripheral blood has been examined. Anti-arrhythmic agents (ethmozine, ethacizine, quinidine, disopyramide, amiodarone), used extensively for the control of various heart rhythm disorders, as well as calcium antagonists (verapamil were shown to have a calcium-blocking property. It is demonstrated that the rate of reduction in the total number of extrasystoles in the presence of antiarrhythmic drugs is correlated to the magnitude of their in vitro calcium-blocking effect. It can be assumed that the action of antiarrhythmic drugs is in part mediated by their effect on calcium currents; at the same time, disorders of Ca2+ transport in myocardial cells are a cause of developing arrhythmias. The ability of antiarrhythmic drugs to affect platelet calcium ion currents may be used for preliminary assessment of the efficiency of antiarrhythmic drugs, used clinically to control heart rhythm disorders.

Action Potentials↗
PubMed1989

[Effect of a single oral dose of allapinin in patients with chronic ventricular extrasystole].

Effect of a new antiarrhythmic drug allapinin was studied in 21 patients with chronic ventricular extrasystoles by an acute drug test with single oral dose of the drug controlled by 12-hour Holter monitoring. In 9 cases the dose was 50 mg. Maximal total reduction of ventricular ectopic complexes (VEC) per hour was 67 +/- 28% (mean value); in 5 cases (55%) it exceeded 90% of basal level. At peak of action, PQ interval increased by 15%, QRS--by 14%, QT was not significantly changed. In 14 cases the dose was 75 micrograms. Maximal VEC number reduction per hour was on the average 89 +/- 18% and in 12 cases (88%) exceeded 90%. PQ increased by 22%, QRS--by 23% and QT by 9% though JT was not changed (average peak values). It is thus concluded that single oral dose of allapinin has pronounced antiarrhythmic effect in patients with VEC and influences ECG intervals in the way characteristic for class IC antiarrhythmic drugs. The degree of the effect depends on the dose.

Aconitine↗
PubMed1989

[Mechanism of depressing effect of diazepam on the blood pressure and on ventricular extrasystoles induced by hypothalamic stimulation in the rabbit].

Experiments were carried out on 62 rabbits anesthetized with urethane and chloralose and immobilized with gallamine triethiodide under artificial ventilation. Ventricular extrasystoles were induced by electrical stimulation of the hypothalamic defence area (HVE). Following intravenous administration of diazepam (0.5 mg/kg), the pressor response and HVE induced by electrical stimulation of the hypothalamus were attenuated, as blood pressure (BP) dropped. Bilateral microinjection of flurazepam (200 micrograms in 0.5 microliters) or GABA (3 micrograms in 0.5 microliters) into the rostral ventrolateral medulla (rVLM) resulted in a significant decrease in BP, and pressor response during hypothalamic stimulation as well as reduction in the amount of HVE. Bilateral microinjection of picrotoxin (7.5 micrograms in 0.5 microliters) into the rVLM facilitated HVE and increased BP. Microinjection of flurazepam, GABA of the same doses into the caudal ventrolateral medulla (cVLM), however, had no such effect. The depressant effect of intravenous injection of diazepam could be prevented by bilateral microinjection of GABA receptor antagonist bicuculline (3 micrograms in 0.5 microliters) or picrotoxin (7.5 micrograms in 0.5 microliters) into the rVLM. Whereas bilateral microinjection of atropine (0.25 micrograms in 0.5 microliters), scopolamine (0.15 micrograms in 0.5 microliters), naloxone (0.5 micrograms in 0.5 microliters), strychnine (1 microgram in 0.5 microliters) into the rVLM no depressant effect was observed. These results suggest that the depressant effect of diazepam on BP, the pressor response and HVE may be mediated by activation of the GABA receptors in the rVLM.

Animals↗
PubMed1989

[Inhibitory action of intracerebroventricular injections of norepinephrine and clonidine on ventricular extrasystoles induced by stimulating hypothalamus in rabbits].

The effects of bilateral intracerebroventricular (icv) injections of norepinephrine (NE) and clonidine on hypothalamic stimulation-induced ventricular extrasystoles (VE) were investigated in alpha-chloralose and urethane anaesthetized rabbits. NE and clonidine reduced the number of HVE. The effects of NE were antagonized by pretreatment with phentolamine and yohimbine, but unaffected by pretreatment with prazosin. Pretreatment with yohimbine could also abolish the effects of clonidine. It is concluded that the effects of reduction in VE induced by NE and clonidine may be mediated by activating central alpha 2-adrenoceptors rather than alpha 1-adrenoceptors.

Animals↗
PubMed1989

[Fetal bradycardia caused by arrhythmia. Apropos of a case of blocked staggered atrial extrasystole].

The author reports a case of fetal bradycardia with a rate of 75 beats per minute, with atrial extrasystoles and an intermittent auriculo-ventricular functional block. Cases have rarely been described because the condition is often not recognized. Bradycardia can be diagnosed as a sign of fetal distress and may lead to procedures which are not helpful. Ultrasound has become the mainstay of diagnosis. The arrhythmia is usually an isolated feature without causing any trouble, and it usually disappears by itself before or soon after delivery. This does not mean that the cause of the arrhythmia should not be sought carefully and that the fetus should not have careful monitoring during pregnancy and in labour (including fetal pH sampling); in general arrangements should be made for a paediatrician to take over the case after birth. This article reviews the different types of fetal bradycardia and classifies them into three groups: sinus bradycardias and sino-auricular dysfunctions auriculo-ventricular blocks which may or may not be associated with a congenital malformation and often occur if the mother has a collagen disease with the presence of anti-Ro antibodies, and paradoxal bradycardias. A system of management of these cases is suggested.

Adult↗
PubMed1980

[Medical treatment of extrasystole and tachycardia (author's transl)].

The more recent antiarrhythmic drugs sometimes with more complex action extend the therapeutic possibilities. In addition, numerous other substances are in clinical trial. An ideal antiarrhythmic agent with a reliable action, persistent effective levels, easily absorbable and with few side effects is not found among them. The indication for therapy in ventricular extrasystole is made on the grounds of an ominous ECG criteria and a presumed clinical threat. Controversial results of lidocaine therapy of acute mayocardial infarction are possibly due to pharmacokinetic factors. For "inhomogeneous repolarization" with increased tendency to ventricular fibrillation inducing drugs should be avoided. Malignant cardiac rhythm irregularities possible leading to sudden death require systemic therapeutical testing. In this case, combinations of antiarrhythmic drugs have the highest effectiveness.

Action Potentials↗
PubMed1980

ECG recognition of extent of acute myocardial infarction in ventricular extrasystoles.

A patient has an ECG on admission to the hospital that demonstrated acute transmural inferior and anterolateral infarction. Charges of additional transmural anteroseptal infarction were evident in ventricular extrasystoles but not in conducted sinus beats. The patient died five days after admission, and autopsy confirmed the presence of fresh anteroseptal infarction, in addition to inferolateral and right ventricular infarction.

Cardiac Complexes, Premature↗
PubMed1980

The spontaneous variation in the pattern of ventricular extrasystoles in patients recently recovered from an acute myocardial infarction.

Twelve patients between the ages of 40 and 68 years with myocardial infarction 1-6 months earlier were subjected to 24 h of ambulatory ECG monitoring for 2 consecutive d. In six patients with an average of less than 5 ventricular extrasystoles (VE) per hour during the first day, the pattern of the arrhythmias was both quantitatively and qualitatively unchanged from day to day. In six patients with an average of greater than 60 VE/h the first day, the number of VE were reduced significantly from the first to second day--in four patients by greater than 50%. The variation was greater after a day-to-day comparison than within the individual days following the division of the 24 h into 6-h periods. In general, the ventricular arrhythmias varied less following a qualitative rather than a quantitative evaluation. The evaluation of the effect of an antiarrhythmic drug in postmyocardial infarction patients requires that a considerable spontaneous variation should be taken into account when the patient is to be used as his own control. If a duration of monitoring of 24 h is employed both prior to and after the commencement of treatment, then the ventricular arrhythmias must practically disappear before the antiarrhythmic effect may be said to be documented.

Adult↗
PubMedDate not supplied

[Time of ventricular extrasystole and its relation to ventricular tachycardia in patients with myocardial infarct].

The coupling time of ventricular extrasystoles (VE) leading to 41 episodes of ventricular tachycardia (VT) in 35 patients with acute myocardial infarction (AMI) was studied regarding the measurement of the precocity index (R-R/QT) and vulnerability index (R-R x QT/R-R') described by other authors. A comparative group was studied in 50 VE of other patients with AMI but without VT. The majority of episodes (83%) of VT were originated by VE with a prematurity index of more than 1 (VE with coupling intervals longer than the QT duration of the previous cardiac cycle, R-R' > QT). The vulnerability index, with reported "dangerous" values of 1.1 to 1.4, was less than 1 in 92.6% of cases of VT and in 100% of VE without VT. A new index, delta QT, for the study of the abnormality of the QT interval respect to normal values (+/-.04") and its relation to the coupling time of the VE was also measured but did not show any difference among groups. In conclusion, none of the indexes were useful as predictor of ectopic beats that can produce VT in patients with AMI. We suggest that VE ocurring in patients with AMI should be suppressed disregarding the prematurity of diming of their appearance.

Acute Disease↗
PubMed1980

[Effect of the pacing interval and extrasystole on amplitude and damping of diastolic oscillations in the rabbit papillary muscle].

Diastolic mechanical oscillations of right ventricular rabbit papillary muscles investigated at 15 degrees C in the perfusion chamber were analysed using a relaxation model with 6 parameters. From this analysis follows that the first diastolic oscillation amplitude plotted against the driving interval ("interval amplitude curve" of the first diastolic oscillation) shows tow maxima thus differing from the shape of the interval strength curve of the preceding driven contraction. It is concluded that the amplitude of diastolic oscillations is less determined by the Ca-amount released from the sarcoplasmic reticulum during the action potential than by the frequency of processes which effect the Ca release and the Ca-sequestration. The damping ratio varies within the range of tested driving intervals (0.36 to 10 s). After an extrasystole damping ratio and period of diastolic oscillation are diminished compared with the values after regularly driven contractions.

Animals↗
PubMed1981

[Effect of beta receptor blockaders on exercise induced extrasystoles].

The effect of a beta-receptor-blocking drug (200 mg Acebutolol pr os) on exercise-stimulated extrabeats (ES) by an ergometrical test was studied in 56 subjects. A reduction of the frequency of premature beats to minimally 50% was considered to be a positive result, which was found in 32 subjects. The best result could be observed in old people, in supraventricular and in the case of a fairly low number of ES. On the other hand the effect was smaller in young people, in ventricular and in frequent extra beats. In three cases polytopic extrasystoles and sinus arrhytmia appeared, which were not observed before. The results give some therapeutical hints. Further they stress the necessity to test the effect of an antiarrhythmical treatment in the individual case.

Acebutolol↗
PubMed1981

[Bundle of His extrasystoles as a cause for A-V block and junctional tachycardia (author's transl)].

The electrophysiological findings in two cases with premature beats arising from the bundle of His are presented. In the first case, the nonconducted impulses led to a functional first and second degree A-V block of the following sinus beats due to retrograde concealed conduction. In addition, very early premature beats from the bundle of His were conducted retrogradely to the atrium simulating blocked premature atrial beats. In the second patient, the premature beats appeared as bigeminy after each sinus beat. As the sinus beats and the extrasystoles from the bundle of His showed a left bundle branch block pattern, a ventricular tachycardia was suspected from the findings in the surface ECG. The reported cases demonstrate the clinical value of the His bundle electrography in patients with bradycardic and tachycardic rhythm disturbances.

Adult↗
PubMed1982

[Observations and significance of extrasystole in very young athletes].

80 very young football players (from 8 to 12) have been examined for three months by some clinical and instrumental cardiologic tests (starting E.C.G. and after graduated stresses on a football court). The starting E.C.G. showed variable extresystolic arrhythmias in 8 subjects, without any sure signs of a cardiopathy, to point out by deeper tests (such as polygraphic, echocardiographic test and rx heart teleradiography). The above-mentioned arrhythmias felt the effects of training variably, since they regressed in 6 cases, however two subjects needed a pharmacological intervention. They are still talking over the meaning to give to extrasystolic arrhythmias in very young people in evaluation of attitude to agonism and in programming training.

Age Factors↗
PubMed1983

[Detection and long-term treatment of ventricular extrasystole in patients with ischemic heart disease].

One-hour monitoring and bicycle ergometric testing revealed frequent (more than 10 per hour) and complicated ventricular extrasystoles in 105 patients. They were distributed between the treatment and control groups. Long-term treatment with beta-blocking agents reduced the frequency of sudden death and repeated myocardial infarction in the treated group as compared to the controls.

Adult↗
PubMed1983

Effects of flecainide on atrial and ventricular stimulation thresholds to repetitive extrasystoles and fibrillation and on "2nd Phase" ventricular arrhythmias in dogs.

Repetitive extrasystole and fibrillation thresholds were assessed by various methods of programmed atrial and ventricular stimulation using intracavitary bipolar electrode catheters and a microcomputer based 3-channel stimulator as previously described. "2nd Phase" ventricular arrhythmias were produced by ligation of the left descending coronary artery. 2,5-Bis-(2,2,2-trifluoroethoxy)-N-(2-piperidylmethyl)benzamide acetate (flecainide, R 818, Tambocor) caused a significant increase of the atrial and ventricular fibrillation thresholds. The antifibrillatory action was similar in atrial and ventricular tissues. "2nd Phase" ventricular arrhythmias were dose-dependently reduced or abolished completely. Similar doses were required to suppress spontaneous arrhythmic activity and to increase the fibrillation thresholds. Thus, flecainide proved to be a powerful antiarrhythmic agent with strong antifibrillatory properties in therapeutic doses. It may be a promising drug for the treatment of atrial and ventricular reentrant arrhythmias.

Animals↗