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Biomedical subjects

H Schieffer

Publications and source records attributed to H Schieffer.

At least 37 records · Page 2Linked to original sources
PubMed1990

[Coincidence of hypertensive fundus changes and regulatory disorders of peripheral microcirculation. II--Skeletal muscles].

In patients with hypertensive fundus changes considerable morphologic changes of the entire vascular system may be assumed. In the present study, the effects of these processes on the partial oxygen pressure of the skeletal musculature were investigated in 62 patients via a macro puncture electrode placed in the tibial muscle. The extent of fundus changes and the reduction in muscular partial oxygen pressure were found to be correlated. With advancing stages of fundus changes, blood flow measured in the common carotid artery decreased. Vascular changes which are clearly recognizable in the hypertensive fundus thus appear to be accompanied by a deterioration in partial oxygen pressure in muscular tissue and restriction of flow in the macrocirculation.

Aged↗
PubMed1990

Optimised function for determining time to peak creatine kinase and creatine kinase-MB as non-invasive reperfusion indicators after thrombolytic therapy in acute myocardial infarction.

STUDY OBJECTIVE: The aim of the study was to investigate the use of an optimised function to approximate and interpolate the time course of serum creatine kinase and creatine kinase-MB values after thrombolytic therapy in acute myocardial infarction. DESIGN: A three parameter interpolating function was developed which approximates the time course of serum enzyme levels. In the proposed function, time to peak creatine kinase and maximum of creatine kinase determined from raw data were used as starting parameters of the non-linear interpolation routine, thus providing ideal starting conditions for the iteration. The efficacy of the function was compared with that of three other functions cited in published reports (log-normal distribution function, modified gamma density function, three compartment function). SUBJECTS: Serum enzyme data from 20 patients with acute myocardial infarction were used in the comparisons. The patients have all been treated with anisoylated plasminogen streptokinase activator complex. RESULTS: In comparison with the other models, deviations of the experimental model function from the raw data were minimal. The fit remained stable for time intervals between blood samples of up to 6 h. CONCLUSIONS - Due to its numerical stability, the function outlined in this study is suitable for large clinical reperfusion trials. In the case of uncomplicated infarctions without thrombolytic therapy, the area under the creatine kinase activity curve could be directly calculated in terms of maximum activity and time to peak.

Anistreplase↗
PubMed1990

[Third replacement of the tricuspid valve in combined aortic-tricuspid defect].

The implantation of valvular prostheses in tricuspid position is problematic due to the slow blood flow in the low-pressure system with the risk of valvular thromboses. Today there are prostheses with supportable low transvalvular gradients; nevertheless, the risk of valvular thromboses is, in spite of anticoagulation, increased by using mechanical prostheses in tricuspid position. We report on a 51-year-old woman in whom a dysfunction of the Starr Edwards ball prosthesis 15 years after its implantation in the tricuspid position was diagnosed. The prosthesis, which was unable to function due to connective tissue proliferation, was replaced by a St. Jude Medical prosthetic valve, which also presented a disturbed function a few days after the implantation. Because of a suspected valve thrombosis the patient was treated with rt-PA-lysis which proved to be ineffective. Thus it was inevitable to implant a third tricuspid valve; this time a bioprosthesis was used.

Aortic Valve↗
PubMed1989

[Hemodilution in patients with multiple morbidity and peripheral arterial occlusive disease].

The treatment of multi-morbid patients suffering from peripheral arterial occlusive disease (PAOD) is rendered difficult due to concomitant diseases such as coronary heart disease, chronic obstructive pulmonary affection, arterial hypertension or diabetes mellitus. Haemodilution can be a clinically efficient therapy for some of the concomitant diseases as well. It is, however, necessary to use a weak colloidal solution which has no additional volume effect as an iso-oncotic substance. Hydroxyethyl starch 200/0.5 6% meets all these demands. In a double-blind, placebo-controlled study over a period of 6 weeks a marked and significant increase of almost 40% in painfree walking distance was achieved for 19 of 37 multi-morbid patients with PAOD II by moderate hypervolaemic haemodilution with venesections. Besides the clinical improvement, blood fluidity also increased through a reduction in haematocrit, plasma viscosity, and erythrocyte aggregation.

Adult↗
PubMed1989

Effects of fish oil capsules in two dosages on blood pressure, platelet functions, haemorheological and clinical chemistry parameters in apparently healthy subjects.

The effects of a fish oil concentrate with an omega-3 fatty acid content of 42% was determined in two dosages in a double-blind, placebo-controlled study with a parallel group comparison over a period of 5 weeks with 30 healthy subjects. The daily intake chosen was four and eight capsules corresponding to 1.26 or 2.52 g omega-3 fatty acids. Plasma viscosity, erythrocyte rigidity and systolic blood pressure were significantly decreased (p less than 0.01) after a 5-week administration of 2.52 g omega-3 fatty acid daily. The reduction in vitamin E concentration was significant (p less than 0.01) only in the low-dose fish oil group. Lipids and lipoproteins remained unchanged throughout this experiment.

Adult↗
PubMed1988

Antianginal efficacy of gallopamil in comparison to nifedipine.

In a randomized double-blind crossover trial 30 patients with chronic stable angina were studied to compare the antianginal actions of gallopamil (150 mg/day) and nifedipine. With the initial nifedipine dose of 60 mg/day, the trial had to be stopped because of severe exacerbation of angina in 3 patients of the nifedipine group. Twenty-one patients were entered into a second protocol with the nifedipine dose reduced to 30 mg/day. Compared to the preceding placebo period, the exercise time to onset of angina (+ 30%, P less than 0.01) and the total exercise time (+ 18%, P less than 0.01) were prolonged by gallopamil but not by nifedipine (+ 20 and 13%, respectively, not significant) with no significant difference between the test drugs. Four patients became free of angina during exercise testing with gallopamil therapy and one patient with nifedipine. Both agents significantly reduced ST depression at maximal comparable workload by 77% (gallopamil) and 52% (nifedipine) compared with placebo; the difference between the drugs reached borderline significance (P = 0.055). The increase in heart rate and the rate-pressure product at maximal comparable workload was less with gallopamil than with nifedipine (P less than 0.01). In contrast to nifedipine, very few side effects were reported with gallopamil. Thus, gallopamil is an effective antianginal agent whose therapeutic to toxic ratio appears to be superior to that of nifedipine.

Adult↗
PubMed1988

Atrial signal variations and pacemaker malsensing during exercise: a study in the time and frequency domain.

To give some explanation for atrial malsensing in dual chamber pacing that occurs only during exercise, atrial electrograms from 33 patients were telemetrically recorded and analyzed in both the time and frequency domains. During exercise, an overall decrease from 6.4 +/- 1.9 to 5.6 +/- 1.9 mV (-11%) in the atrial signal amplitude was noted. Despite considerable variability among patients, marked changes occurred in 15 patients whose signals diminished by 11 to 49%. Slew rates showed a similar decrease from 1.35 +/- 0.45 to 1.18 +/- 0.45 V/s (-10.8%), with individual changes of as much as -51%. Signal attenuation in the time domain correlated well with frequency data, exhibiting a highly significant reduction of signal energy between 25 and 105 Hz. However, spectral distribution changed from rest to exercise, with a relative increase of signal energy in the range between 5 and 25 Hz and a decrease at higher frequencies. Individual changes differed widely when low (15 to 65 Hz) and high (65 to 115 Hz) frequencies were compared, but in a group of 11 patients signal attenuation in the high frequency band was more pronounced (-45%) than in the low frequency band (-23%). The clinical impact of the change in frequency distribution during ergometry was visualized by computer simulation of two different (low and high bandpass) filters. Although in individual patients, both characteristics may be favorable with respect to atrial sensing, it was observed in 11 patients that high pass filtering attenuates signal amplitudes by 10 to 24% in excess of the variation without filtering.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Isovolemic hemodilution in patients with coronary heart disease].

In the age of cellsavers patients suffering from coronary heart disease are diluted to a hematocrit of 20% or even less during a surgical intervention in the coronaries and they leave the operating room with a hematocrit of 30%. On the other hand, a hemodilution to a level of 30% in patients with coronary heart disease represents a contraindication due to the limited coronary reserve. On the occasion of the collection of autologue blood, before vascular surgery or for therapeutical hemodilution, the hematocrit was reduced from 45 to 35% by means of an isovolemic hemodilution with 500 ml of Haes 200/0.5 10% in 50 patients. In the load-ECG the pressure X frequency-product and the dyspnoe decreased significantly. The microcirculation in the nailfold and the systemical blood fluidity increased significantly. As in 22% of the patients a deterioration was stated, we propose to dilute all the patients who have to undergo a coronary vessel operation without exclusion criteria once isovolemically and to stress them before and afterwards. The patients having a clinical defict should be diluted intraoperatively only to 30% and postoperatively not under 35%.

Angina Pectoris↗
PubMed1988

[Dose-related effect of nicainoprol (CAS 924) on basic electrophysiologic parameters in patients with and without diseases of the heart conduction system].

The dose-dependent effects of nicainoprol (1 and 2 mg/kg/h), a new antiarrhythmic drug, on invasive electrophysiological parameters were evaluated in 28 patients during diagnostic electrophysiologic studies. The most pronounced effects by nicainoprol were observed on the specialized AV conduction system. The intranodal (1 mg/kg/h: A-H interval: 92 +/- 19 ms to 107 +/- 25 ms, p less than 0.002, n = 13; 2 mg/kg/h: 92 +/- 18 ms to 114 +/- 27 ms, p less than 0.001, n = 16) and, in particular, the infranodal conduction time (1 mg/kg/h: H-V interval: 45 +/- 5 ms to 52 +/- 9 ms, p less than 0.001, n = 15; 2 mg/kg/h: 45 +/- 6 ms to 58 +/- 10 ms, p less than 0.0001, n = 18) were delayed in a dose-dependent fashion. With the higher dose, there was a highly significant prolongation of the AV nodal Wenckebach cycle length (380 +/- 69 ms to 440 +/- 79 ms, p less than 0.0001, n = 13) as well as of the effective (368 +/- 112 ms to 428 +/- 108 ms, p less than 0.001, n = 12) and functional refractory periods (470 +/- 102 ms to 521 +/- 135 ms, p less than 0.001, n = 15). The intraatrial conduction time was slightly prolonged for both doses, the intraventricular conduction time increased significantly with the higher dose (89 +/- 12 ms to 102 +/- 19 ms, p less than 0.001, n = 19). In contrast, there were only small changes of right atrial and right ventricular refractorion.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗
PubMed1986

Withdrawal of long-term amrinone therapy in patients with congestive heart failure: a placebo controlled trial.

To verify favourable long-term effects, 14 patients with chronic congestive heart failure, NYHA class II-IV, who had been treated with oral amrinone for 8-15 months with apparent clinical benefit, had the drug withdrawn according to a 12 week placebo controlled double-blind crossover protocol. Evaluation was performed noninvasively by means of exercise stress test, echocardiogram, radionuclide angiography and systolic time intervals. None of these variables were significantly changed after discontinuation of amrinone, regardless of whether placebo was introduced during the first (group B, N = 7) or the second 6 week period (group A, N = 5), nor when the medication was finally openly withheld for another 6 weeks. In 2 further group A patients, premature termination of the trial was due to deterioration of symptoms on blinded amrinone. Hence, no sustained drug related effects could be proven by controlled withdrawal of long-term amrinone in this trial.

Adult↗
PubMed1985

[Atrial flutter and atrial fibrillation by DDD stimulation].

136 patients were followed after implantation a DDD pacemaker (PM) for a total of 1,919 patient-months (m = 14.1 months/patient). 22/136 patients had one or more episodes of atrial flutter or fibrillation (AF) postoperatively. In 121/136 patients (group A) AF had not been documented before, in 4 it was unknown at the time of implantation, but was verified retrospectively (group B). 11 patients (group C) had a positive history of previous AF. Post implantation 7.4% in group A and 81.8% in group C developed AF. In patients with sick sinus syndrome (SSS) the incidence was 10/37 (27%), in those with AV block (AV) 6/77 (7.8%) and in cases with both SSS and AV 6/22 (27.3%). The first AF episode occurred during the implantation itself (n = 2) or during the hospital course in 9/22 patients (A: 11%, B/C: 64% early attacks), and later on in 13 with a time delay of 1-24 months (m = 8.5, 8 patients) in group A and 2-15 months (m = 6.6, 4 patients) in groups B/C. 2 patients of group C had no AF episodes post implantation. In the individual patient the number of attacks ranged from 1 to 3 (10.4/100 patient-months) in group A and from 1 to 6 (20.1/100 patient-months) in groups B/C. During AF 16/22 patients had a ventricular rate of 110-185, m = 132 bpm. In 6 patients the tachycardia was mediated by the PM and in 10 by fast intrinsic AV conduction. 1 patient with SSS, 2 with SSS + AV (spontaneous ventricular rate less than 45 bpm) and 3 with AV needed ventricular backup-pacing during AF. In 7 patients a total of 15 attacks of atrial flutter could be terminated by atrial overdrive pacing, in 5 of these episodes by temporary high rate A00 stimulation via the implanted pacemaker lead system. Otherwise AF was converted to sinus rhythm by antiarrhythmic drugs. After termination AF often recurred, but only 3 patients developed chronic atrial fibrillation. In 2 patients a ventricular rate greater than 180 bpm during AF reverted the PM to asynchronous mode, a possible cause of ventricular fibrillation in one. No other complications due to the PM itself have been encountered. AF, therefore, common during DDD pacing, even in patients without any AF history before implant. Both the incidence and the recurrence of AF depend on the presence or absence of previous atrial arrhythmias.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Incidence of ventricular arrhythmia relative to the QT interval in spontaneous intracranial hemorrhages].

A prospective study was done in 54 patients with acute spontaneous intracranial haemorrhage, 27 of them with subarachnoid bleeding and 27 with primary intracerebral haemorrhage. The frequency of ventricular arrhythmias was registered by continuous long-term ECG and the incidence of QT prolongation by daily standard ECG registration. Prolongation of frequency-corrected QT-interval (QTc) developed in 9 patients with subarachnoid haemorrhage and in 10 with intracerebral haemorrhage. For assessment of time-relation between QT-interval and ventricular arrhythmias the results of corresponding long-term ECG and standard ECG were used and two groups were defined: group A (149 tapes) = QTc less than or equal to 450 ms, group B (43 tapes) = QTc greater than 450 ms. In group B singular frequent ventricular extrasystoles, couplets and non-persistent ventricular tachycardias occurred more frequently though not significantly so. Persistent ventricular tachycardias occurred significantly more frequently in group B (14% vs. 1%, P less than 0.01). In three tapes of group B, all of them with QTc prolongation of more than 550 ms persistent ventricular tachycardias with typical "torsade de pointes " morphology were seen. The results show that QTc prolongation of more than 450 ms occurs in a third and significant ventricular arrhythmia in nearly half of patients with spontaneous intracranial haemorrhage. Persistent ventricular tachycardias occur almost only in cases of QTc-prolongation. Pronounced QTc prolongation of more than 550 ms is rare. However, it can give rise to torsade de pointes and ventricular fibrillation.

Adult↗
PubMed1984

[Long-term therapy of angina pectoris. Evaluation of the effectiveness and tolerance of oxyfedrine in ambulatory patients].

In an open multicentre trial, the clinical efficacy and tolerance of Oxyfedrine, (Ildamen forte) was evaluated in 123 patients with angina pectoris. After three months of treatment the frequency of anginal attacks and nitroglycerin consumption were markedly reduced in 80 percent, after 12 months in 88% of patients; 37 percent were totally angina-free and 50% were without need for sublingual nitroglycerin. Side-effects were reported by 23.6% of patients during the first months of treatment with a total of eight symptoms being reported in 40 instances; after one year, the incidence of side-effects was substantially reduced to 8 instances in 6 percent of patients. Laboratory investigation were not significantly affected: in 11 patients minor deviations from the reference range were noted without clinical relevance. Dropouts due do drug intolerance were not observed.

Adult↗