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Biomedical subjects

F Bender

Publications and source records attributed to F Bender.

At least 37 records · Page 2Linked to original sources
PubMed1985

Benefit-risk ratio in the treatment of tachyarrhythmias. A clinical judgement.

The goal of antiarrhythmic treatment--the well-being of the patient and improvement of prognosis--requires careful clinical investigation and observation with monitoring of the arrhythmia during long term treatment. A few compounds now in use are under investigation for their efficacy in selectively depressing sinus tachycardia, or tachycardias involving the atrioventricular node. No ideal drug is yet available, nor is likely in the near future, for treating the complex problem of arrhythmogenesis. A favourable benefit-risk ratio for flecainide has been shown by many authors during the last 7 years and greatest interest now centres on its use in malignant arrhythmias. More studies in high risk patients are necessary for a better understanding of the proarrhythmic properties of antiarrhythmic drugs, thus paving the way for prevention and treatment of these unwanted effects.

Anti-Arrhythmia Agents↗
PubMed1985

[Acute and long-term antiarrhythmia effect of encainide in chronic atrial extrasystole].

The antiarrhythmic effects of Encainide in acute intravenous and long-term oral therapy were investigated in 10 patients suffering from chronic atrial ectopic beats previously non-responsive to conventional therapy. The efficacy of Encainide was assessed by 24-hour ECG monitoring during the acute i.v. application and in 4 week intervals over a period of 4 to 6 months. Plasma concentrations of Encainide and the O-demethyl- (ODE) and 3-methoxy-O-demethyl metabolites (3-MODE) were determined after i.v. administration and during oral therapy. A significant reduction of arrhythmias by 76% was found after 1.0 mg/kg Encainide given intravenously. Atrial ectopic beats with bundle branch block QRS-morphology were reduced by more than 90% after only 0.5 mg/kg. During long-term oral therapy 6 of the 9 patients were treated successfully. Following i.v. administration Encainide-plasma concentrations rapidly decreased with a half life of approximately 75 min in the final distribution phase. During oral therapy Encainide levels were not detectable under steady state conditions 4 to 6 hours after the last dose, or they were only minimal, but the average concentrations of ODE and 3-MODE were 71.3 +/- 21.3 and 75.6 +/- 13.5 ng/ml. Encainide increased PR interval and QRS duration significantly. QT-interval changed as a result of the QRS-prolongation. Encainide was well tolerated during acute and chronic therapy. No severe side effects were seen, except in one case, in which dose reduction by 50% was necessary because of blurred vision.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

[Therapy of orthostatic dysregulation with gepefrin. Study with continuous telemetric blood pressure monitoring].

The action of the new pressor agent gepefrine (D form of 3-hydroxyphenyl-2-aminopropan) was evaluated in 16 patients with typical clinical symptoms of orthostatic adjustment disorders. The blood pressure measured in the brachial artery (percutaneous puncture and catheterisation according to the Seldinger technique) and the electrocardiogram were transmitted by telemetry and continuously documented under standard conditions at rest, on standing and during a step test. One hour after oral administration of 30 mg or 45 mg gepefrine the blood pressure increased significantly at rest and more markedly on standing and during the step test. Gepefrine led to a reduction in pathological orthostatic regulation during the early phase as well as to the prevention of subjective and objective signs of orthostatic adjustment disorder during the late phase. Patients with insufficient rise in blood pressure during the step test (80 watts) showed after gepefrine a distinct tendency towards normalisation and the regression of subjective states of exhaustion. Gepefrine caused on average no substantive alternations in heart rate during all phases of the investigation. Complications or side-effects due to the method or the medicament were not observed.

Adolescent↗
PubMed1985

Assessment of the antiarrhythmic profile of the new class I agent diprafenone.

The antiarrhythmic profile of the new compound diprafenone was evaluated using various dog models relevant to conditions in humans. In 8 animals, dose related effects on intracardiac conduction, atrial and ventricular refractoriness, fibrillation thresholds and on hemodynamics were determined. In this part of the study also the comparative actions of propafenone were assessed (8 animals). IN another 28 dogs the antiarrhythmic and antifibrillatory actions of diprafenone following short-term coronary occlusion and subsequent release were established. In additional 16 animals the effects of diprafenone on "delayed" reperfusion arrhythmias following release of coronary artery occlusion after 2 h and on stimulus-induced ventricular tachycardia in acute myocardial infarction were investigated. The results show: Diprafenone slows conduction through all parts of the AV-conduction system. The AH-interval is significantly prolonged, QRS-duration and ventricular repolarization are slightly lengthened, and both the atrial and ventricular refractory periods and fibrillation thresholds are markedly increased. Heart rate is slowed, aortic pressure and cardiac output are not significantly changed. Following acute short-term coronary artery occlusion, the incidence of ventricular fibrillation is reduced, and the drop in the ventricular fibrillation threshold is diminished. By contrast, the frequency of ventricular fibrillation after release of short-term occlusion is not influenced. "Delayed" reperfusion arrhythmias, however, are completely abolished, and initiation of ventricular tachycardia in myocardial infarction can be easily prevented. With a predominant local anesthetic mechanism of action and a potential additional beta-sympatholytic activity, the new compound displays close similarities to propafenone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Clinical aspects of the aging heart].

Diagnostic and therapeutic procedures in the ageing heart require a holistic approach considering polypathology and polypharmacology of the diseased organism. Adaptation to stress is inadequate due to a delayed and reduced reaction of the sympathetic nervous system. Vagal disturbances are discussed as well. Coronary heart disease and its complications, bradyarrhythmias and premature atrial and ventricular contractions and congestive heart failure dominate the clinical picture of the elderly patient. These clinical entities represent the main causes for death at higher age. Pharmacotherapy has to be adjusted according to differences in absorption, pharmacokinetics and pharmacodynamics, drug interferences and an age specific spectrum of side effects.

Age Factors↗
PubMed1984

[Long-term therapy with flecainide].

The effect of the new antiarrhythmic drug Flecainide was examined in a controlled long-term study (1 to 44 months [x = 17.7 +/- 12.4]) in 36 patients, aged 18 to 76 years (x = 44 +/- 16.3), suffering from ventricular arrhythmias. In 12 cases coronary heart disease, in 11 cases myocarditis, in 2 cases each of dilatative cardiomyopathy and mitral valve prolapse syndrome, and one in case each of combined aortic and mitral valve disease and postoperative condition of Fallot Trilogy was present. In 7 cases the etiology of the dysrhythmias could not be elucidated. 18 patients had been treated before by more than 3 other antiarrhythmic drugs without sufficient result. The daily dose administered was assessed by the degree of the dysrhythmias and the response to the drug. In most cases 300-400 mg Flecainide was given. The therapeutic success was assessed by 24 h Holter-ECG before and during therapy. In most cases two registrations were performed before and three registrations during therapy. In 29 patients (81%) a rate reduction of VES over 70% could be observed. Rate reduction of VT (n = 8) was total in 5 cases, in one case over 90%, in two cases over 70%. Salvos (n = 10) were abolished in 7 cases and reduced over 90% in two and over 70% in one of the cases. R-on-T-phenomena (n = 2) disappeared completely. An increase of rate or degree of the dysrhythmias was never observed. In no case had therapy to be interrupted due to severe side effects. Changes of laboratory values were not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

[Treatment of heart arrhythmias with calcium antagonists].

The depressing effect of calcium antagonists on sinus node and AV node function is well documented in the experimental animal and in man. Other cardiac fibers may be depolarized to a level at which the slow inward current determines the rise of the action potential and may become sensitive to calcium antagonists, thus abolishing extrasystoles or tachycardias. However, effects of the drugs on heart rate, coronary perfusion, and pre- and afterload of the left ventricle must be taken into account, which may affect the electrophysiologic basis for the dysrhythmia. The conversion rate of atrial fibrillation to sinus rhythm (n = 200) amounted to 77% when quinidine was combined with verapamil. Monotherapy of these drugs or combination of quinidine with diltiazem or pindolol did not elevate the atrial fibrillation threshold compared to quinidine/verapamil. Reduced ventricular fibrillation thresholds in the experimental animal after coronary occlusion increased significantly during the early reperfusion period after verapamil and nifedipine by cardioprotection. Due to a reduced renal clearance the bio-availability of digoxin increased with a concomitant medication of quinidine and verapamil.

Arrhythmias, Cardiac↗
PubMed1984

[Echocardiographic detection of persistent myocardial sinusoids].

In a 33-year-old woman the diagnosis of isolated persistent myocardial sinusoids could be established by 2-D-echocardiography and ventriculography. This anomaly has been reported in infants with atresia of semilunar valves and intact ventricular septum, or in combination with anomalies of the coronary vessels. In adults myocardial sinusoids have only been observed with a communication to the coronary arteries. To our knowledge, no other case of severe cardiac disease due to isolated myocardial sinusoids has so far been published.

Adult↗
PubMed1984

[Changes in scintigraphically determined regional blood volume in coronary patients treated with the new substance teopranitol].

To evaluate the effects of the new compound teopranitol (KC 046) on blood volume distribution scintigraphic measurements were performed in 10 patients with coronary heart disease. The data were compared to the results in 10 untreated patients with coronary heart disease. The differences in blood volume distribution were calculated by the ratio of the impulse rates thorax/abdomen, thorax/thigh, thorax/shank and heart/total impulse rates assessed by scintigraphy, following in vivo labeling of red blood cells with 99m-Tc, before and after i.v. injection of 0.04 mg KC 046/kg body weight. A significant decrease of the ratios could be found, whereas the data in the untreated group did not change significantly. It is concluded from these results that the clinical improvement of the patients with coronary heart disease treated by KC 046 is caused by a significant shift of blood volume from the thoracic region into the abdomen and the legs, thus decreasing the preload of the left ventricle.

Aged↗
PubMed1984

[Hemodynamic effects of the new calcium antagonist nimodipine in normal and increased blood pressure].

The new compound nimodipine, a calcium channel-blocking agent, belongs to the dihydropyridine derivatives. In experimental studies it exhibits a preferential vasodilator action on cerebral vascular smooth muscle. We studied the hemodynamic effects of nimodipine in 8 normotensives (5 male, 3 female, mean age 47.8 +/- 3.7 years) and 8 patients (6 male, 2 female, mean age 57.4 +/- 2.6 years) with a systolic blood pressure greater than or equal to 165 mm Hg. After administration of nimodipine in hourly increasing doses of 0.015 mg/kg/h, 0.030 mg/kg/h and 0.045 mg/kg/h by an i.v. infusion, the following parameters were measured continuously: systolic, diastolic and mean arterial pressure (brachial artery), systolic and diastolic pulmonary artery pressure, pulmonary wedge pressure, cardiac and stroke volume index, total vascular resistance, stroke work index, blood flow in the legs by venous occlusion plethysmography and heart rate. Nimodipine provided a significant reduction of systolic, diastolic and mean arterial blood pressures when 0.015 and 0.030 mg/kg/h were infused. The higher dose of 0.045 mg/kg/h did not reduce these values any further. In normotensives cardiac index increased significantly. Hardly any changes in heart rate were observed. Total vascular resistance decreased significantly. Preload remained nearly unchanged. From these results it is concluded that the new calcium antagonist nimodipine provides potent vasodilator effects with a moderate reduction of blood pressure and without significant changes in heart rate.

Adult↗
PubMed1984

[Comparative studies on the anti-arrhythmic and anti-fibrillatory effectiveness of verapamil and nifedipine following acute coronary artery occlusion and reperfusion].

The ability of the two calcium-antagonists Verapamil and Nifedipine to reduce ventricular electrical instability following acute transient coronary artery occlusion and release and to prevent ventricular arrhythmias, particularly fibrillation, was evaluated on a total of 25 anaesthetized and artificially ventilated dogs. In all animals repeated coronary occlusions, lasting 20 min each, with a reperfusion period of 120 min between subsequent ligations, were performed. Time course and extent of ventricular ectopic activity were continuously registered, and the changes in ventricular vulnerability were assessed by measuring the ventricular fibrillation threshold at different times both after coronary artery occlusion and reperfusion. Verapamil displayed strong antiarrhythmic and antifibrillatory action on ventricular arrhythmias during occlusion. Ventricular tachycardia and fibrillation were completely prevented during phase la of arrhythmia (2nd to 10th min after coronary artery occlusion) and significantly reduced during phase lb (15th to 20th min after coronary artery occlusion). By contrast, Nifedipine failed to exert any antiarrhythmic and antifibrillatory effect, respectively. Following release of coronary artery occlusion, none of the compounds proved to reduce the frequency of ventricular fibrillation immediately after the onset of reperfusion. However, either drug was able to accelerate significantly the increase in the ventricular fibrillation threshold during the early post-reperfusion period. The different antiarrhythmic and antifibrillatory action of Verapamil and Nifedipine after coronary artery occlusion can be assumed to result from differences in the electropharmacological properties of these compounds, whereas the enhancement of the electrical stability of the myocardium after release of coronary artery occlusion may be due to "cardio-protective" effects of these drugs.

Animals↗
PubMed1984

Antiarrhythmic effects of stirocainide in acute myocardial infarction.

Ventricular arrhythmias, especially ventricular fibrillation, are assumed to be a main cause of sudden death during the first 24 h of acute myocardial infarction. Effective prophylaxis and acute suppression of these life-threatening rhythm disturbances are a major therapeutic problem. The present study was undertaken to investigate the efficacy of the new antiarrhythmic compound stirocainide (2-(1-benzylidene)cycloheptenimino-oxyethyl-diisopropylamine -2-butenedionate, Th 494) in suppressing "2nd phase arrhythmias" arising from large anteroseptal myocardial infarctions using a standardized experimental canine preparation. Our results demonstrate that "2nd phase arrhythmias"--i.e. frequent ventricular ectopics, tachycardias, salvos, and R-on-T phenomena--are reduced by 80-90% (sometimes even completely abolished) by stirocainide (dose: 4 mg/kg within 3 min, followed by 300 micrograms/kg X min over a 20-min period). The administration of the drug at the dose used does not produce severe cardiodepression, but intraventricular conduction time is significantly prolonged. Thus, Th 494 is a highly effective antiarrhythmic agent in acute myocardial infarction, and further experimental and clinical investigations on its antiarrhythmic and antifibrillatory properties may lead to beneficial therapeutic results.

Animals↗
PubMed1983

[Divergent time courses of ventricular vulnerability of the heart to ventricular tachycardias and ventricular fibrillation in the early necrosis stage of acute experimental myocardial infarct].

UNLABELLED: Early necrosis in acute experimental myocardial infarction is characterized by severe ventricular dysrhythmias beginning approx. 6 hours after coronary artery occlusion and persisting for 2-5 days. It was the aim of this study to investigate the comparative changes in ventricular vulnerability to spontaneous and stimulus-induced tachycardia and fibrillation during early necrosis 6-18 hours following acute coronary artery occlusion. RESULTS: 1) The thresholds for repetitive extrasystoles and for ventricular fibrillation determined via electrodes placed on to the endocardium of the right and left ventricle outside of the ischemic area are within the normal range of the non-ischemic heart. 2) Both stimulation thresholds increase significantly within the area of infarction and in many cases are not inducible any more after 18 hours of ischemia, whatever amount of current is applied. 3) Sustained ventricular tachycardia can be induced in about 30% of cases after an occlusion lasting approx. 6 hours and in about 80% after an occlusion period of 18 hours. 4) Electrically induced ventricular tachycardias differ from spontaneously occurring VT in so far as the former appear to be due to a reentry mechanism, whereas the latter seem to be "accelerated ventricular rhythms" and thus of focal origin. Our results demonstrate that enhanced ventricular vulnerability during early necrosis in acute myocardial infarction is predominantly due to ventricular tachycardia rather than to ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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↗
PubMed1983

Comparative study of stress reactions during oral surgery after pindolol and metoprolol.

The prophylactic effect of a single oral dose of 5 mg pindolol (P) or 100 mg metoprolol (M) on sympathetic and adrenergic stress reactions was investigated by a double blind study in 40 patients undergoing oral surgery. A reduction of systolic and diastolic blood pressure as well as heart rate was noted after both, P and M, as was the increase of these parameters during surgery. Adrenaline-, noradrenaline- and c-AMP-level were reduced after systematic beta-blockade by P only, not after M. The increased lipolysis and glycolysis during surgery were prevented by P only. The stimulation of the hypothalamic and adrenal stress reactions were not influenced by either P or M. The application of the systematic beta-blocker with ISA (P) only was suited to prevent the increase of catecholamine levels in plasma and peripheral receptor stimulation.

Adrenocorticotropic Hormone↗