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Biomedical subjects

B Lüderitz

Publications and source records attributed to B Lüderitz.

At least 451 records · Page 25Linked to original sources
PubMed1976

[Arrhythmias in the Wolff-Parkinson-White syndrome (author's transl)].

The clinical relevance of the Wolff-Parkinson-White syndrome is determined by the occurrence of cardiac arrhythmias due to the syndrome. Occurrence and severity of the cardiac arrhythmias are mainly dependant on the electrophysiological properties of the accessory atrioventricular bypass or the refractory period of the regular and irregular pathways respectively. Programmed electrical stimulation allows the study of these properties directly in man. The treatment in patients with WPW syndrome suffering from re-entry tachyarrhythmias should be directed to an interruption of the tachycardia circuit. During sinus rhythm a suppression of spontaneously occurring ectopic beats which may initiate a tachycardia is indicated.

Adult↗
PubMed1975

[Hemodynamics, left ventricular volumes and compliance in 167 patients with congenital and acquired heart disease (author's transl)].

In 167 patients with congenital and acquired heart disease (ventricular septum defect (VSD), atrial septum defect (ASD), mitral stenosis (MS), mitral insufficiency (MI), combined mitral stenosis and insufficiency (MV) aortic stenosis (AS), aortic insufficiency (AI), combined aortic stenosis and insufficiency (AV), idiopathic hypertrophic subaortic stenosis (HOK) hemodynamic measures (arterial pressure, right and left heart pressures, cardiac output, cardiac index, stroke volume, cardiac work), left ventricular volumes (endiastolic volume, endsystolic volume, ejection fraction, regurgitant flow) and diastolic pressure-volume relationships (on the basis of diastolic pressure-volume changes) were determined during routine right and left heart catheterization and left ventriculography. 1...

Adolescent↗
PubMed1975

[Pacemaker treatment of tachyarrhythmias by programmed rate-related interval stimulation(author's transl)].

Programmed rate-related interval stimulation proved to be a low-risk method when applied to 74 patients with drug-resistant ventricular tachycardia or runs of ventricular extrasystoles as precursors of tachycardia. Atrial flutter was converted to atrial filbrillation and sinus rhythm by atrial interval-related multiple stimulations. Tachycardias, which could not be terminated by simple or double stimulation, were successfully suppressed by sequential ventricular R-R related multiple stimulations. Rare-related stimulation has proved to be an alternative method of treating tachy-arrhythmias unresponsive to conventional means.

Aged↗
PubMed1975

Comparative study of sinoatrial conduction time and sinus node recovery time.

Atrial stimulation were performed in 5 normal patients (group A) and 4 patients with electrocardiographic evidence of sinoatrial disease (group B). The technique of premature atrial stimulation was used to calculate sinoatrial conduction time. Rapid atrial pacing was applied to measure maximum sinus node recovery time. In 4 cases both stimulation methods were repeated after intravenous administration of atropine Group A had a sinoatrial conduction time of 56 ms +/- 11 (SD) and a maximum sinus node recovery time of 1122 ms +/- 158. In 3 out of 4 patients with sinus node dysfunction a prolongation of sinoatrial conduction time could be demonstrated (145, 105, and 150 ms). In addition, one showed probable sinus node exit block after premature atrial stimulation. Sinus node recovery time was excessively prolonged in 2 (3880 and 3215 ms) and normal in the other 2 patients with sinoatrial disease (1330 and 1275 ms). Atropine leads to a decrease of sinoatrial conduction time. Results indicate that sinus node recovery time may not be a reliable indicator of sinus node automaticity if sinoatrial conduction is disturbed. The premature atrial stimulation technique makes it possible to study the pattern of sinoatrial conduction and to evaluate its reaction to therapeutic drugs.

Adult↗
PubMed1975

Influence of glycosides on myocardial potassium and sodium concentration in acute and chronic potassium deficiency.

The analytical assay of intracellular potassium ([Ki]) and sodium ([Nai]) concentration of guinea pig papillary muscle measured in in vitro experiments shows that: 1) 5 X 10(-7) M g-strophanthin causes a decrease of [Ki] under control conditions, in acute as well as in chronic potassium deficiency, 2) a more marked glycoside effect is seen when the extracellular potassium concentration is reduced from 4.7 to 2mEq/1; this finding, therefore, is in good agreement with the observation that glucoside binding to its receptor at the cellular membrane is enhanced when potassium concentration is decreased, 3) whereas in chronic potassium deficiency normal [Ki] and [Nai] are maintained, acute potassium deficiency is accompanied by a loss of cellular K and gain of cellular Na. Under the influence of cardioactive glycosides, in chronic potassium depletion higher intracellular potassium and lower intracellular sodium concentrations are maintained than in acute potassium depletion. It is supposed tha t the net changes which are caused by a reduction of [Ke] in acute potassium deficiency in contrast to chronical potassium deficiency predispose to glycoside toxicity. These changes may therefore be the cause of the clinical observation that acute hypokalemia is associated with a greater glycoside sensitivity than chronic potassium deficiency.

Acute Disease↗