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Biomedical subjects

W Lengfelder

Publications and source records attributed to W Lengfelder.

28 records · Page 2Linked to original sources
PubMed1984

[Programmed stimulation in patients with malignant ventricular arrhythmia. II: Individual optimization of anti-arrhythmia therapy].

The major purpose of programmed ventricular stimulation in patients with malignant ventricular arrhythmias (sustained ventricular tachycardia/ventricular fibrillation) is not the diagnostic or prognostic evaluation but the individual optimization of antiarrhythmic therapy. For successful antiarrhythmic treatment, the choice of an adequate parameter of efficacy is of outstanding relevance: in patients with frequent daily episodes of malignant ventricular arrhythmias, proper treatment can be based on Holter monitoring; however, in patients with infrequent but life-threatening attacks, Holter monitory appears to be inadequate and programmed stimulation is the method of choice for proper treatment decisions. A total of 394 serial pharmaco-electrophysiological studies was performed in 82 patients with inducible sustained ventricular tachycardia or ventricular fibrillation. During the acute serial studies, one drug was tested each subsequent day using short-term intravenous infusions. The only criterion for drug efficacy was prevention of inducible sustained ventricular tachycardia or ventricular fibrillation that had been reproducibly initiated under control conditions before antiarrhythmic treatment. At least one preventive drug was found in approximately 2/3rd of the patients. Following serial acute studies using intravenous administration, an effective agent was selected and given orally. Programmed stimulation was repeated usually after three days demonstrating reproducibility of preventive efficacy in 90% of the trials. During a subsequent follow-up period of an average of 15 months, the number of acute events (9%) including sudden death or life-threatening recurrences of malignant ventricular arrhythmias was significantly reduced as compared to patients with non-optimized therapy (54%; p less than 0.05). The number of cardiac deaths due to progressive heart failures was not significantly different in patients placed on optimized or non-optimized antiarrhythmic treatment.

Administration, Oral↗
PubMed1982

Electrophysiological effects of glucose-insulin-potassium on sinus node function in patients with and without sinus node dysfunction.

The electrophysiological effects of glucose (100 g)-insulin (20 U)-potassium (10 mmol X litre-1) infusion (GIK) on three parameters of sinus node function were studied in 14 control subjects (mean age 53 +/- 14 yr) and 11 patients (mean age 50 +/- 17 yr) with sinus node dysfunction (SND). In a first series of experiments the response to GIK was examined in nine control and 11 SND patients. Following GIK, the mean spontaneous cycle length decreased by 17% (671 to 560 ms; P less than 0.01) in the control group and by 33% (1066 to 715 ms; P less than 0.001) in the SND patients; this difference between both groups was statistically significant (P less than 0.01). In the control group mean corrected sinus node recovery time (CRST) and calculated sinoatrial conduction time (SACT; n = 6) were not significantly altered after GIK. In SND patients GIK decreased the mean value of CSRT by 40% (693 to 416 ms; P less than 0.05) and of calculated SACT (n = 6) by 27% (130 to 95 ms; P less than 0.05); prolonged secondary pauses following termination of rapid atrial pacing in SND patients were also shortened. In a second series of experiments, mannitol (100 g, iv) was administered in five control patients but had no significant effect on the electrophysiological parameters tested. Plasma levels of glucose were significantly increased, by 500% (P less than 0.01), after GIK; plasma potassium and sodium concentrations decreased by 7 and 5% (P less than 0.05). The results indicate that GIK had a beneficial effect on sinus node dysfunction.

Adult↗
PubMed1982

Arrhythmogenic effects of toxic concentrations of the antiarrhythmic drug lorcainide on the isolated canine ventricle.

The effect of the new antiarrhythmic drug lorcainide was studied on the specialized conducting system of isolated canine ventricle. Transmembrane action potentials were recorded simultaneously from three subendocardial sites within the ventricular basis, free wall and apex. At concentrations of 3 x 10(-6) and 2.4 x 10(-5) M, lorcainide caused a dose-dependent decrease in maximum rates of rise and in amplitude of the action potential; 0.6 x 10(-6) M had no significant effect, resting potential and action potential duration remained unchanged with 0.6 x 10(-6) M and 3 x 10(-6) M. The most prominent effect of 2.4 x 10(-6) M lorcainide was the appearance of an increasing notch resulting in clear separation of the action potential in an initial short spike depolarization (50-120 msec) with or without a subsequent plateau depolarization 280-370 msec). Both components demonstrated an independent and inhomogeneous conduction through functionally different pathways. Changes in stimulation rate or premature stimuli resulted in nonstimulated reexcitations resembling bigemini, ventricular tachycardia or regional ventricular fibrillation. The results indicate that dissociation of the action potential in two components is due to toxic alterations of ionic channels of the fiber membrane and that nonstimulated reexcitations are due to reentry via functionally fast and slow pathways.

Action Potentials↗
PubMed1981

[Hodgkin's disease. Results of diagnosis and therapy (author's transl)].

The principles of modern diagnosis and therapy of lymphogranulomatosis are largely standardized today. Whereas the 50% probability survival rate in a group of patients diagnosed before 1970 was about 2 years, 23 out of 30 with standardized diagnosis and therapy have survived until now. Full remission was obtained in 21 of 30 patients. In spite of these encouraging results, the synopsis of the course of the disease shows that relapses and complications must be reckoned with in lymphogranulomatosis. Side effects of therapy may also acquire considerable clinical importance in the individual case.

Adolescent↗
PubMed1981

[Differential diagnosis of creatine kinase elevation: hypothyroid myopathy (author's transl)].

An increase of creatine kinase (CK) activity in serum as a result of myopathy of skeletal muscle can point to hypothyroidism. In the differential diagnosis from myocardial infarction determination of CK isoenzymes is the most suitable test. In three women (aged 56, 70 and 72 years) with hypothyroid myopathy demonstrated in this manner, administration of thyroid hormone preparations normalised CK activity within 2-4 weeks. A little later thyroid hormone levels in serum were also normal, while histological changes in the musculature persisted rather longer.

Aged↗
PubMed1979

[Early detection of bronchial cancer (author's transl)].

Compared with the results of a retrospective study (1954) of early detecting bronchial cancer, our present investigations showed, that females are relatively more concerned than formerly, that the climax of frequency has removed for about ten years to the aged, that more non-smokers are concerned than formerly (16% to 3.5% respectively) and that the time between manifestation of the first symptoms and admittance to hospital has shortened remarkably (one month 26%, three months 33% = 59% compared with 28.3%). In four patients the disease has been discovered by x-ray mass-screening, two of them were nevertheless admitted to hospital too late. Whereas the value of tomography has been established, the results of bronchoscopy ameliorated. Only one patient could be operated: perhaps the shift of age for one decade and a certain negative selection may be responsible for these disappointing results. The x-ray-examination in 2 levels must be performed in every adult male patient, even if bronchopulmonal symptoms do not exist. Moreover, exposed persons (e.g. strong smokers) must be controlled by x-ray examination in regular intervals. It is in this sense, that we see the scope of x-ray mass-screening.

Age Factors↗