PubMed Health⌕ Search

Biomedical subjects

R Gmeiner

Publications and source records attributed to R Gmeiner.

17 recordsLinked to original sources
PubMed1979

Intracardiac electrophysiological effects of lorcainide in man.

The electrophysiological effects of lorcainide 1.25 or 2.5 mg/kg given iv over 2 or 4 min, were studied in 21 patients with normal and diseased impulse formation and conduction, by means of intracardiac recording and stimulation. Sinus rate and the effective atrial refractory period rose following both doses of lorcainide. The corrected sinus node recovery time rose only after lorcainide 2.5 mg/kg and then most markedly in patients with sinus node dysfunction. The P-A interval remained unchanged following the drug. The A-H interval during sinus rhythm, and the pooled A-H intervals during atrial pacing, increased slightly, and the functional and effective A-V nodal refactory period changed variably. Wenckebach periods above the bundle of His occurred at lower atrial pacing rates following both doses of lorcainide in 7 patients, at the same atrial pacing rate in 9 and at higher rates in 3. H-V intervals, pooled H-V intervals and QRS-width lengthened in all patients, most markedly in cases with a conduction delay below the His bundle, who had received lorcainide 2.5 mg/kg. Thus, lorcainide shares some electrophysiological properties with procainamide and aprindine. Higher doses should be used with caution in patients with pre-existing conduction delay below the bundle His.

Acetanilides↗
PubMed1979

Concealed accessory pathway and dual AV conduction: drug-dependent reentrant tachycardia.

Electrophysiological studies were performed in a patient with paroxysmal supraventricular tachycardia and a normal surface ECG at the time of the study. Premature atrial stimulation revealed dual AV conduction and an echo zone during AV conduction over the fast and the slow pathway. The prolongation of the AV conduction time by a calcium antagonist, Ro 11-1781, permitted the induction of tachycardias via both pathways. Premature ventricular stimulation yielded constant VA conduction times with activation of the low right atrium before the high right atrium before the left atrium. During the tachycardia, premature right ventricular beats conducted to the atrium at a time when the AV node and the His bundle would be refractory. The study suggests the simultaneous occurrence of an occult accessory bundle connecting the right ventricle to the right atrium and dual AV conduction.

Adult↗
PubMed1979

Effect on paroxysmal re-entrant supraventricular tachycardia of a drug affecting calcium transport (Ro 11-1781).

The effect of Ro 11-1781, a drug that affects calcium transport, in 10 patients with paroxysmal supraventricular tachycardia (PSVT), was studied by intracardiac recording and stimulation. The re-entry circuit involved an accessory pathway that conducted only in the ventriculo-atrial direction in 5 patients, and was confined to the A-V node in 5 cases. Prior to administration of Ro 11-1781 tachycardia could be initiated in all patients. An intravenous bolus of 2 mg/kg during PSVT terminated the tachycardia in all cases by blockade in the A-V node. Ro 11-1781 lengthened the A-V nodal conduction time as well as the functional and effective refractory period of the A-V node. The effective refractory period of the "fast" pathway was variably changed. After Ro 11-1781 the tachycardia zone was abolished in 3 cases, reduced in 3, increased in 3 and was converted to an echo zone in 1. The ability to sustain the PSVT was lost in one subject. The heart rate during PSVT was slowed following Ro 11-1781. Ro 11-1781 appears to be useful for the termination of PSVT, but its ability to prevent PSVT varies. Beneficial effects include abolition or narrowing of the tachycardia zone, loss of the ability to sustain PSVT and a reduction in heart rate during PSVT. The widening of the tachycardia zone may be harmful.

Adult↗
PubMed1979

The effect of a new calcium antagonist (Ro 11-1781) on the cardiac conduction system in man.

Using His bundle electrograms and atrial pacing the effects of Ro 11-1781, a new calcium antagonist, was studied in 13 patients with normal A--V conduction. Following an intravenous bolus of 2 mg/kg Ro 11-1781 the A--V nodal conduction time (A--H interval) was prolonged in all patients during sinus rhythm, atrial incremental and premature pacing. Wenckebach periods above the bundle of His occurred at lower atrial driving rates following the drug. The functional and effective refractory period of the A--V node were prolonged after the administration of Ro 11-1781. No significant effect of Ro 11-1781 on the remainder of the conduction system was observed. Heart rate and the corrected sinus node recovery time changed variably. The increase of the A--H time in response to Ro 11-1781 was completely reversed by Atropine.

Adolescent↗
PubMed1978

[Inactivation of implanted demand pacemaker through external stimulation].

External chest wall stimulation was performed in 87 patients in order to overdrive and thereby suppress the implanted pacemaker. The impossibility to inactivate the implanted pacer suggested a disturbed "sensing" function in 12 patients. Marked changes of the escape rhythm were found in 77 patients with suppressable pacemaker when compared with the tracings before pacemaker implantation. Increasing degree of A-V block or marked changes in heart rate were observed in 14 of 35 cases with advanced A-V block. Minor alterations were noted in cases with sick sinus syndrome and atrial fibrillation. Overdrive suppression is a helpful method for the selection of pacemaker dependent patients.

Aged↗
PubMed1978

[Lorcainid--electrophysiologic examinations of a new anti-arrhythmia agent].

The electrophysiologic properties of Lorcainide (1.25 and 2.5 mg/kg) were studied on 21 patients by intracardiac electrograms and atrial stimulation. A prolongation of the H-V interval, widening of QRS duration but only minor changes in A-H interval were found. The effective refractory period of the atria increased, the effective and functional refractory periods of the A-V node changed variable following Lorcainide. There was a slight increase in heart rate and the sinus node recovery time was longer after 2.5 mg/kg of the drug. The major site of action of Lorcainide in man appears to be the His-Purkinje system. In electrophysiologic terms the new antiarrhythmic agent closely resembles Aprindine.

Acetanilides↗
PubMed1978

[Prophylaxis of supraventricular paroxysmal tachycardias on the basis of electrophysiologic examinations].

Paroxysmal supraventricular tachycardias (PSVT) were classified with regard to electrophysiologic criteria in 12 cases. In 6 patients the reentry circuit of the PSVT involved a concealed accessory connection, in 6 patients the reentry circuit was confined to the A-V node. Different antiarrhythmic drugs were administered orally over a 4 week period, the frequency of attacks and possible side effects were recorded. In patients with accessory pathway metoprolol (n = 3), ajmalin (n = 3), Aprindine (n = 1) and verapamil (n = 1) prevented the occurrence of PSVT. Verapamil, Ro 11-1781, metoprolol and digitalis were effective in A-V nodal reentry. PSVT could be prevented in all but one patient by at least one drug.

Adult↗
PubMed1977

[The effect of ouabain on sinus node function and intracardiac conduction (author's transl)].

The effect of 0.5 mg Ouabain (O) i.v. on sinus node function and on intracardiac conduction was studied by His bundle electrography and atrial stimulation. 7 patients with normal sinus node function and av conduction (group I), 5 patients with sick sinus syndrome (group II), and 5 patients with av block of changing degree (group III) were examined. 2 additional patients had simultaneous sinus node dysfunction and av block (group II/III). The sinus node recovery time was prolonged in 6 patients, the av block was located proximal to the His bundle in 4 patients and distal to the His bundle in 3 patients. The spontaneous sinus rate decreased in group I and remained unchanged in group II and III after O. The PA interval increased slightly after O in groups II and III, the AH interval during sinus rhythm was prolonged after O in groups II and III and in the whole group together. During atrial pacing, the stimulus-His-time was increased in each group when compared at identical stimulation rates. In 4 of 7 patients av block type Wenckebach appeared at a lower stilmulation rate after O. The HV interval remained unaltered after O, the sinus node recovery time varied after O. Phenytoin had no positive effect on the changes observed after O. Unwanted actions of O such as increased bradycardia or increased av conduction disturbances were not observed. O appears to be reasonably safe in most patients with sick-sinus syndrome and changing av block.

Adult↗
PubMed1977

[The effect of Ro 11-1781, a calciumantagonist, on atrioventricular conduction (author's transl)].

The effect of an intravenous bolus of 1 mg/kg Ro 11-1781, a new calciumantagonist, on sinus node automaticity and intracardiac conduction was studied by His-bundle electrography and atrial stimulation. During sinus rhythm, no significant action of Ro 11-1781 on rate, P-A-interval, A-H interval, and H-V-interval was observed. The sinus node recovery time remained unaltered. On atrial stimulation, the St-H-interval was significantly (p less than 0.001) prolonged after Ro 11-1781. Wenckebach Periods occurred at lower stimulation rates in all patients after Ro 11-1781. It is concluded that Ro 11-1781 prolongs av nodal conduction and may be of therapeutic value in the treatment of supraventricular arrhythmias.

Adult↗
PubMed1977

Reduction of pulmonary hypertension by nitroprusside.

The action of nitroprusside on pulmonary circulation was studied in patients with pulmonary hypertension due to mitral stenosis (group I) or to primary lung disease (group II) and in patients with normal pulmonary artery pressure (group III). Nitroprusside 20 microgram/min decreased systolic and mean pulmonary artery pressure in groups I and II while higher doses were necessary to produce a similar pressure reduction in group III. Diastolic pulmonary artery pressure was reduced by 40 microgram/min nitroprusside in all groups. Systemic arterial pressure declined during nitroprusside infusion similary in all groups in a dose-related manner; cardiac index remained unaltered. Pulmonary vascular resistance was reduced by 20 microgram/min nitroprusside in group I, not below 200 microgram/min nitroprusside in group II and remained unchanged in group III. Peripheral vascular resistance declined in all groups with nitroprusside infusion. The study suggests direct relaxation of the pulmonary vasculature by nitroprusside.

Adolescent↗
PubMed1976

[Lowering of pulmonary-arterial pressure with nitroprusside in mitral stenosis and cor pulmonale (author's transl)].

Nitroprusside was infused intravenously (20, 40, 80 and 200 mug/min) in nine patients with pulmonary hypertension due to mitral stenosis (group I), nine with precapillary pulmonary hypertension associated with primary lung disease (group II) and nine with normal pulmonary-arterial pressures (group III). The mean pulmonary-arterial pressure was markedly reduced at a rate of 20 mug/min in group I and II, while higher doses were necessary in group III to produce a similar effect. Mean arterial pressure was decreased in all three groups and was dose-related. Heart rate rose, stroke volume fell during nitroprusside administration, while cardiac output remained unchanged. Pulmonary vascular resistance was reduced on 20 mug/min in group I, but only on 200 mug/min or more in group II, and unchanged at all dosages in group III. Peripheral vascular resistance declined in all three groups on nitroprusside infusion, which is apparently of value in the short-term lowering of pulmonary hypertension.

Blood Pressure↗
PubMed1976

[Influence of atrial contraction on stroke volume in pacemaker stimulation].

The contribution of the atrial systole to the stroke volume was studied in 12 patients with implanted pacemakers by means of impedance-cardiography. P-ST-intervals between 70 and 200 msec. increased the stroke volume as compared with systoles without preceding P-waves. A maximal stroke volume was observed with a P-ST-interval of 130 msec. The increase of the stroke volume by 33% justifies the application of atrial triggered pacemakers in selected cases, mainly in younger patients despite of the technical limitations of these pacemaker systems.

Aged↗
PubMed1975

[Recurrent ventricular fibrillation (author's transl)].

106 episodes of ventricular fibrillation were observed in 11 patients, 9 of whom had acute myocardial infarctions. The heart rate before the onset of ventricular fibrillation was below 50 in two episodes, 60 to 100 in 63, and above 100 in 41. 83 attacks of ventricular fibrillation were preceded by fewer than five ventricular premature beats, 23 by more than five, 19 by more than ten. Multifocal ventricular premature beats occurred ten times, runs of ventricular premature beats 11 times, with only three falling into the vulnerable period. Left bundle branch block was present in three patients, right bundle branch block with left anterior hemiblock in two, isolated left anterior hemiblock in two, left posterior hemiblock in one. 85 episodes of ventricular fibrillation occurred during antiarrhythmic treatment, 72 during lidocaine administration. Antiarrhythmic drugs were effective only in reducing the number of ventricular premature beats. The only successful treatment of recurrent episodes of ventricular fibrillation was repeated electrical countershocks.

Aged↗
PubMed1975

Effect of sodium nitroprusside on myocardial performance and venous tone.

The action of sodium nitroprusside upon the mechanical performance of the isolated, working rat heart and on isolated bull veins has been studied. Cumulative concentrations of 1--1000 ng sodium nitroprusside per ml had no effect on left ventricular pressure, end-diastolic left ventricular pressure, dp/dtmax, cardiac output and calculated wall stiffness of isolated rat hearts with constant rate, preload and afterload. Isolated strips of bull veins contracted with noradrenaline showed a dose dependent relaxation by sodium nitroprusside in concentrations of 5--1000 ng per ml. This study shows that sodium nitroprusside has no direct effect on myocardial contractility and causes venous relaxation.

Animals↗
PubMed1975

Hypoxic, isolated rat heart: hemodynamic and metabolic effects of nitroglycerin.

The purpose of the study was to evaluate the effects of nitroglycerin on the mechanical and metabolic performance of the mammalian heart without interference from peripheral vascular and neurohumoral influences. Isolated rat hearts were perfused with a buffer containing 1 mug of alcoholic nitroglycerin/ml or an equivalent amount of alcohol. Mechanical performance was analyzed during external and isovolumic work; all hearts were subjected to mild hypoxia. Heart rate was kept constant by pacing. At constant atrial filling pressures end diastolic pressures and calculated wall stiffness were not significantly different for controls and nitroglycerin. Afterload, as quantitated by mean aortic pressure, was the same for both groups. Peak-systolic left ventricular pressure and dp/dt max during ejection and isovolumic work were significantly reduced by hypoxia (p less than 0.001), but not changed by nitroglycerin. Cardiac output, mean systolic left ventricular pressure, work, oxygen consumption, and calculated efficiency were decreased by hypoxia (p less than 0.001); lactate production was enhanced by the hypoxic state (p less than 0.001). Nitroglycerin had no influence on these parameters in either state. It is concluded that at constant rate, preload and afterload nitroglycerin has no effect on the mechanical performance and energy formation by aerobic and anaerobic means in the fully oxygenated and mild hypoxic state.

Animals↗