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Biomedical subjects

H Jahrmärker

Publications and source records attributed to H Jahrmärker.

At least 19 recordsLinked to original sources
PubMed1990

[What is the role of ethics commissions for clinical research?].

Professional and drug development laws require that each project involving human research is submitted to a specially appointed independent committee (Ethics Committee) to ensure conformity with the ethical principles of the medical profession (Declaration of Helsinki). Today the public demands this prerequisite for clinical research. The main goal is to protect the patient or proband from unjustified risks. The interest of the subject must always prevail over the interests of science and society.

Ethics Committees↗
PubMed1985

Effect of the calcium antagonist diltiazem on atrioventricular conduction in chronic atrial fibrillation.

The effect of oral diltiazem treatment on the mean ventricular rate was studied in 10 patients with stable atrial fibrillation (AF). The profile of mean ventricular rate was analyzed by means of 24-hour electrocardiographic recordings. Both single-dose (120 mg) and maintenance therapy (80 mg 3 times daily) reduced the mean ventricular rate significantly. After the single dose, the effect set in after 120 +/- 40 minutes (mean +/- standard deviation) and persisted for 347 +/- 84 minutes. Histograms of RR intervals were plotted and their changes after diltiazem therapy were also analyzed. The shortest and longest atrioventricular (AV) conduction times were defined as 5% and 95% values of the cumulative frequency curve, respectively. There were 2 distinct types of the RR-interval histographic changes: In 50% of the patients, the longest and shortest RR intervals prolonged proportionately; in the other 50%, the longest intervals increased disproportionately. Results indicate that oral diltiazem treatment can significantly decrease the mean ventricular rate in patients with AF by influencing the concealed conduction in the AV node. The changes of the RR-interval histograms suggest that in 50% of the patients, the increase of the concealed conduction was probably caused primarily by the increase of AF rate, and in 50% both increased AF rate and prolonged refractory period in the AV node contributed to the increase of concealed conduction.

Adult↗
PubMed1983

[Optimizing therapeutic success in aortocoronary bypass operations].

Left ventricular function improves after aortocoronary bypass operation in 80% of preoperative postextrasystolic reversible asynergic segments, but this usually does not occur in preoperative postextrasystolic irreversible segments. Improvement is often seen even without revascularisation of the corresponding vessel, when a bypass to another stenosed vessel enables enhanced collateral flow. Therefore, it is recommended to graft as many stenosed vessels as possible, even those corresponding to postextrasystolic irreversible segments, to provide beneficial effects in other segments. To achieve a real complete revascularisation, vessels with about 50% stenosis or total occlusion should also be bypassed. For multiple stenosed vessels sequential graft technique is recommended. In lesions not suitable for grafting an endarterectomy should be performed however the risk of intraoperative infarction should be considered. Platelet inhibition after bypass operation results in a significant increase of patency rate. Low dose acetylsalicylic acid is the treatment of choice and should be started very early postoperatively.

Aspirin↗
PubMed1983

[Comparative studies on the cardiodepressant effect of disopyramide, mexiletine and propafenon].

The effect of clinical antiarrhythmic doses of disopyramide (Di), mexiletine (Me), and propafenon (Pr) on cardiac function was studied in 7 normal volunteers by M-mode echocardiography and the extent of functional changes caused by the three drugs was compared. For each of the substances echocardiographic parameters of left ventricular function were determined before injection, 5-25 min. after an intravenous administration (Di 2.0 mg/kg, Me 3.0 mg/kg, Pr 1.5 mg/kg) at intervals of 5 min., and after 3 days of oral therapy (Di 4 X 200 mg/day, Me 4 X 200 mg/day, Pr 3 X 300 mg/day). Di, Me, and Pr each showed significant negative inotropic activity, though of varying degree. For each drug the effect was more pronounced after intravenous administration than under oral therapy. Maximum decreases in myocardial contraction occurred 5-15 min. after termination of injection, with an increase in endsystolic diameter (Di 30.3%, Me 13.6%, Pr 9.7%), no change in preejection diameter, and a reduction in the percentage and velocity of mean circumferential fiber shortening and systolic ventricular wall thickness (Di 18.1%-45.1%, Me 9.6%-23.7%, Pr 11.8%-16.7%). While the cardiodepressant activity of orally administered Di, Me and Pr did not statistically differ, for the first 20 min. after intravenous administration Di exhibited a marked negative inotropic effect that was significantly greater than those of Me and Pr. In view of the considerable hemodynamic side effects of Di, Me, and Pr observed in this study, the benefit to risk ratio must be evaluated carefully and individually before commencement of antiarrhythmic therapy. Because of its acute and pronounced cardiodepressant activity, intravenous Di should be used with particular caution; a dose reduction and slow injection are recommended in patients with left ventricular dysfunction.

Adult↗
PubMed1983

Anti-ischemic effects of an 80-mg tablet of isosorbide dinitrate in sustained-release form before and after 2 weeks treatment with 80 mg once daily or twice daily.

The purpose of this study was to investigate whether the anti-ischemic effects of a single 80-mg tablet of isosorbide dinitrate in sustained-release form are attenuated after 2 weeks of twice-daily administration. In order to follow a double-blind protocol with respect to the 12-h interval, we also evaluated, in randomized order, another group of patients receiving the tablets once daily. Parameters for assessment of the anti-ischemic effects were changes in exercise-induced ST-segment depression and the simultaneously recorded left ventricular ejection fraction, as determined by radionuclide ventriculography. The ST-segment depression was measured completely blind; the left ventricular ejection fraction was calculated automatically with a clinically validated software. In the group that received the tablets once daily (n = 10) none of the patients showed any signs of attenuation of the beneficial anti-ischemic effects. However, seven of the 12 patients who received the tablets twice daily demonstrated significant attenuation. Thus, based on analysis of the presently available studies, in order to guarantee maintenance of the anti-ischemic benefits, a once-daily high dose of ISDN in sustained-release form (80 mg or even higher) is recommended.

Coronary Disease↗
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↗
PubMed1978

[Measurement of the conduction time within the fascicles of the His-Purkinje-system using endocardial detection (author's transl)].

The conduction time in the 3 fascicles of the His-Purkinje system can be measured by recording the local excitation in the peripheral His-Purkinje system of the right bundle and the anterior and posterior fascicle of the left bundle, in combination with His-bundle recordings. This technique allows a detailed study of the subjunctional conduction and gives information on the conduction pathways in ventricular arrhythmias.

Electrocardiography↗