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Biomedical subjects

K Stangl

Publications and source records attributed to K Stangl.

At least 19 recordsLinked to original sources
PubMed1991

Sex hormone concentrations in men with angiographically assessed coronary artery disease--relationship to obesity and body fat distribution.

The relationship between circulating sex hormone levels and the occurrence of coronary artery disease (CAD) was studied in a group of 274 men undergoing coronary angiography. Hormone levels in men with CAD (n = 200) were compared to those in men found to be free of coronary lesions (n = 74). No significant differences were found for serum concentrations of estradiol, total testosterone, sex-hormone-binding globulin, free androgen index, dehydroepiandrosterone sulfate, or cortisol between the two groups. Serum androgens were negatively correlated to age in both groups, whereas estradiol was weakly associated with total cholesterol in the group of men without CAD. No consistent associations were detected between sex hormone levels and the degree of obesity or the distribution of body fat, the latter being assessed by the ratio of waist-to-hip circumferences. The results of this study do not support a significant role of sex steroid hormones in coronary artery disease in men.

Adult↗
PubMed1991

Acute effects of beta-adrenergic stimulation with dobutamine on the plasma levels of atrial natriuretic peptide and cyclic guanosine monophosphate in patients with chronic heart failure.

In eight patients (63 +/- 7.9 years) with angiographically documented dilated cardiomyopathy, we studied the acute effects of a beta-adrenergic stimulation with dobutamine on the plasma levels of atrial natriuretic peptide (ANP) and cyclic guanosine monophosphate (cGMP). For this purpose, a four-point dose-response curve was prepared for dobutamine starting with an initial dose of 2.5 micrograms kg-1 min-1, which was increased by 2.5 micrograms kg-1 min-1 at a time up to altogether 10 micrograms kg-1 min-1. Each stage lasted 15 min. ANP and cGMP were determined from the mixed venous blood before the start (t0), at 5 micrograms kg-1 min-1 after 30 min (t1), at 10 micrograms kg-1 min-1 after 60 min (t2) and after subsidence of the drug effect after 90 min (t3). ANP dropped from 380 +/- 151 pg ml-1 (normal range up to 55 pg ml-1) by 38% to 235 +/- 90 pg ml-1 after 30 min and by another 17% to 171 +/- 45 pg ml-1 after 60 min. After the effect of dobutamine had subsided, an increase by 41% to 325 +/- 139 was reached. There was a parallel drop of the mean cGMP level from 5.4 +/- 1.4 pmol.ml-1 by 28% to 3.89 +/- 1.4 pmol.ml-1 (30 min) and by another 14% to 3.2 +/- 0.7 pmol.ml-1 (60 min). After 90 min it was 18% below the initial value, being 4.4 +/- 1.3 pmol.ml-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Anti-bradycardia pacemaker therapy: rational choice of system in relation to hemodynamic and prognostic aspects].

UNLABELLED: Currently, the most important indications for pacemaker treatment include high-grade AV-block, the sinus node syndrome, atrial fibrillation with slow ventricular rate as well as the hypersensitive carotid sinus. In the Federal Republic of Germany, 88.5% of the units employed were fixed-rate ventricular single-chamber systems (VVI), in less than 10% dual-chamber systems (DDD) and in 2.4% fixed-rate atrial single-chamber systems (AAI) as well as rate-adaptive systems (VVIR, AAIR). In 1986, a total of 32,000 pacemakers were implanted in the Federal Republic and about 105,000 in the USA. State-of-the-art: Miniaturization of single-chamber systems to less than 20 grams and dual-chamber systems to less than 30 grams has been associated with markedly improved lead technology which has lowered energy requirements. The development of atrial-independent, variable rate systems has enabled rate adaptation in patients who are not candidates for DDD-stimulation or in whom the atrial rate is inadequate. With Holter functions various physiological parameters can be continuously monitored and their response as well as biorhythmicity are analyzed. INDICATIONS: The following guidelines are those of the working group "Cardiac Pacing" of the German Society for Heart and Circulatory Research for the choice of pacemaker systems which are considered to provide the best respective physiologic form of stimulation with the goal of rendering optimal hemodynamics. For characterization of the pacemaker modes, the five-letter NASPE/BPEG code is used. The possibility for single modes, AV-synchrony and rate adaptation as central factors for physiologic stimulation forms is shown in Table 2. Those systems are designated as "physiologic" which reestablish AV-synchrony, that is, pacing modes in which the atria are incorporated With the VAT-, VDD- and DDD-modes there is an additional atrial-triggered rate modulation. In AAI- order DDD/I-modes rate adaptation is independent of the atria (AAIR, DDD/IR) via physiologic parameters while rate-adaptive VVI stimulation does not enable AV-synchrony. Atrioventricular conduction disturbances: Pacemaker treatment is carried out for prevention of Adams-Stokes symptoms and for improvement of the hemodynamic situation. Prognostic implications of pacemaker treatment: With pacemaker treatment the one-year mortality of patients with Adams-Stokes symptoms and/or complete AV-block can be lowered to 5 to 19% from 50 to 70%.(ABSTRACT TRUNCATED AT 400 WORDS)

Bradycardia↗
PubMed1990

Body fat distribution in men with angiographically confirmed coronary artery disease.

Body fat distribution and its relationship to coronary artery disease and established cardiovascular risk factors have been studied in a cohort of 286 men aged between 30 and 74 years undergoing coronary angiography. 207 (72.4%) patients showed stenosis (greater than 30%) or occlusion of one or more coronary arteries. whereas the remaining 79 (27.6%) men were free of coronary lesions and served as a control group. 112 men with angiographically defined coronary artery disease had an additional history of myocardial infarction. Body fat distribution was assessed by determining the waist-to-hip circumference ratio. A stepwise logistic regression analysis revealed that in addition to LDL-cholesterol (P = 0.0001) and age (P = 0.0005) an abdominal type of body fat distribution (P = 0.0129) is also a significant risk indicator for the occurrence of coronary artery disease (CAD) independent of body weight and other factors such as total cholesterol, HDL-cholesterol, triglycerides, insulin, systolic and diastolic blood pressure. The results of this study suggest that an abdominal type of fat distribution is associated with an increased risk of coronary artery disease.

Adipose Tissue↗
PubMed1990

Differences between atrial single chamber pacing (AAI) and ventricular single chamber pacing (VVI) with respect to prognosis and antiarrhythmic effect in patients with sick sinus syndrome.

Several studies suggest different effects of atrial (AAI) and ventricular single chamber pacing (VVI) for sick sinus syndrome with respect to the suppression of atrial tachycardias and to the prognosis. With this aspect in mind, we studied 222 patients with sick sinus syndrome, 110 of whom had been supplied with AAI systems, and 112 with VVI systems, in the period from January 1978 to December 1986. The mean observation period was 53 +/- 28 months. The cumulative 5-year survival rate was not significantly different in the two groups. After subgroups with comparable underlying diseases had been differentiated, patients with coronary heart disease showed a significantly higher survival rate (P less than 0.05) under AAI pacing, and the same was shown for patients with no underlying heart disease (P less than 0.02). The incidence of chronic atrial fibrillation was 6% in the AAI group and 19% in the VVI group. Patients with preexisting atrial tachyarrhythmias showed the lowest incidence of chronic atrial fibrillation under AAI pacing. Under VVI pacing this incidence was a function of the basic rate of the pacemaker systems. In conclusion, the pacing mode seems to have a prognostic importance in spite of all methodological difficulties. A suppressive effect of AAI pacing on atrial dysrhythmias can also be assumed.

Aged↗
PubMed1990

[Acute reduction of increased atrial natriuretic peptide level and cyclic guanosine monophosphate in patients with chronic heart failure caused by beta-adrenergic stimulation with dopexamine hydrochloride. Correlation with hemodynamic parameters].

In eight patients (63 +/- 8 years) with dilated cardiomyopathy, the acute effects of positive inotropic stimulation with dopexamine hydrochloride, a beta-2-agonistic and DA1-dopaminergic catecholamine, on the plasma levels of ANP and cGMP were tested. A four-point dose-response curve was prepared for dopexamine from 1 microgram/kg/min to 4 micrograms/kg/min. Each infusion stage lasted 15 min; ANP and cGMP were taken from the mixed venous blood. Hemodynamic parameters were determined by a Swan-Ganz catheter; cardiac output was determined by thermodilution. ANP dropped by 40% from 348 +/- 124 pg/ml to 208 +/- 70 pg/ml (p less than or equal to 0.01), while cGMP dropped by 25% from 4.8 +/- 1.6 pmol to 3.6 +/- 1.3 pmol/ml at the time of maximum hemodynamic effect after 1 h. Linear regression analyses revealed a significant relationship (p less than or equal to 0.01) between ANP as the independent variable and cGMP as the dependent variable. The hemodynamic determinants of the ANP concentration proved to be--independently of each other--the pulmonary capillary wedge pressure (p less than or equal to 0.01) and the mean right atrial pressure (p less than or equal to 0.01). The results show that chronically elevated ANP and cGMP levels can be strikingly reduced within a short time, whereby ANP and cGMP show similar kinetics. The results suggest a use of ANP and cGMP as humoral parameters in the therapy control of chronic heart failure.

Adrenergic beta-Agonists↗
PubMed1990

[30 years cardiac pacemaker therapy: a status evaluation].

Antibradycardiac pacemaker therapy has become established as one of the most effective forms of cardiological therapy for the indications AV-block, sick sinus syndrome, bradyarrhythmia, and hypersensitive carotid sinus. About 220,000 systems are implanted per year worldwide, about 32,000 in West Germany. Of the pacing modes, the fixed-rate ventricular single chamber systems (VVI) dominate with a share of almost 90%. Prognostic importance: For AV-block, the improvement of the prognosis by pacemaker therapy is unquestionable, since it increases the cumulative survival rates to 81% and 95% after 1 year and 50% to 65% after 5 years. For sick sinus syndrome, VVI-pacing proves to be a symptomatic measure, no prognostic importance can be proven. It is not conclusively clarified at present whether physiological pacing modes (AAI, DDD) have any such importance. Pacemaker therapy also has no prognostic importance for bradyarrhythmia. Hemodynamic importance: Numerous hemodynamic studies show that fixed-rate VVI-pacing fails to produce a long-term hemodynamic improvement for either an AV-block or a sick sinus syndrome. In sick sinus syndrome hemodynamic improvement can only be achieved by physiological pacing modes (AAI, DVI, DDD), whereby the increase in cardiac output is between 11% to 30%. For AV-block a long-term hemodynamic improvement can only be obtained by atrial triggered pacing modes (VAT, VDD, DDD); this is higher than the values of fixed-rate VVI-pacing by 7-25% at rest, or 10-40% under exercise. Similar results with improvements of the exercise hemodynamics between 22% and 66% are reported for rate-modulated single-chamber pacing (VVIR) for AV-block. Future trends: In the fourth decade of pacemaker therapy, developments point toward the "smart pacemaker", toward rate-modulated systems with combinations of parameters, toward rate-modulated dual-chamber systems and universal antibradycardiac and antitachycardiac systems.

Bradycardia↗
PubMed1989

Physical movement sensitive pacing: comparison of two "activity"-triggered pacing systems.

The Activitrax (A) and the Sensolog (S) pulse generator units were compared during bench tests and in patients both under ergometric conditions and during daily activities to determine the susceptibility of both systems to external noise. During the bench tests both pacemakers were mounted on a swingboard and subjected to controlled vibrational force. The patients were divided into two groups of 10 patients each, one group with A and the other with S units; the discriminating power of workload changes was examined under treadmill exercise. In six patients of each group the rate behavior of S and A during daily activities was recorded by Holter monitoring. During bench tests, S and A displayed a frequency-selective mode of operation between 2-70 Hz with the greatest sensitivity between 10-50 Hz. In patients, S showed a significantly higher discriminating power to changes in workload during treadmill exercise. According to y = 0.27x + 85.8 (r = 0.92) the relationship between the power and the pacing rate of S was linear, whereas with y = 0.04x + 89.8 (r = 0.2) the pacing rate of A was almost independent of the given power. The susceptibility to external noise occurring while riding in an auto, streetcar or train with rate increases between 7 ppm and 12 ppm did not significantly differ in both systems. Lying prone on the pacemakers produced brief (less than 1 min) rate increases of 38 ppm (S) and 18 ppm (A), respectively.

Cardiac Pacing, Artificial↗
PubMed1988

Binding sites for atrial natriuretic peptide on platelets in patients with congestive cardiomyopathy.

The aim of the present investigation was to evaluate a possible down-regulation of atrial natriuretic peptide (ANP) binding sites on platelets in patients with chronically elevated ANP plasma levels. The assay procedure was proved to be able to measure the total number of binding sites even in the presence of high ANP plasma levels. We studied 15 adult patients with congestive cardiomyopathy in comparison to 18 healthy volunteers. In the patients the median ANP plasma level (median = 375, range: 155-900 pg ml-1) was about six-fold higher than in the healthy volunteers (median: 55.5, range: 20-90 pg ml-1). The median cyclic guanosine monophosphate (cGMP) plasma level (median: 6.2, range: 2.5-21.4 pmol ml-1) was about three-fold higher than in the healthy volunteers (median: 1.8 range: 1-2.8 pmol ml-1). Despite these markedly elevated ANP and cGMP plasma levels we did not find significantly less receptors per platelet in the patients (median: 19, range: 7.2-60.2) than in the healthy volunteers (median: 24.5, range: 14.8-41.1). Furthermore, there was no difference in the dissociation constants between the patients (median: 10.5, range: 7.9-27.4 pmol l-1) and the control subjects (median: 8.9, range: 5.4-17 pmol l-1).

Aged↗
PubMed1988

Influence of AV synchrony on the plasma levels of atrial natriuretic peptide (ANP) in patients with total AV block.

ANP was determined in 13 patients with DDD pacemakers due to total AV block, at rest and during bicycle ergometry under both pacing modes, DDD and VVI (7O/min). Under DDD pacing, the mean ANP level (normal range 5-95 pg/mL) at rest was 36 +/- 18 pg/mL (mean +/- SD) and increased significantly by the factor of 3.5 to 1 27 pg/mL during exercise (p less than 0.01). By just changing the pacing mode to VVI, the ANP levels rose to 73 +/- 28 pg/mL (p less than O.0 1) at rest (= 203% of DDD resting level) and to 216 +/- 184 pg/mL (= 170% of DDD peak level) during exercise P less than 0.01). These results show that under AV synchronous pacing, the ANP levels we generally lower. A possible explanation for this increased release of ANP during asynchronous VVI pacing is the acute increase of the atrial wall tension which occurs when the atria contacts during the systole against closed AV valves.

Aged↗
PubMed1988

A new multisensor pacing system using stroke volume, respiratory rate, mixed venous oxygen saturation, and temperature, right atrial pressure, right ventricular pressure, and dP/dt.

A new multisensor pacing device using respiratory rate (RR), stroke volume (SV), oxygen saturation (SO2), temperature (T), right atrial pressure (RAP), right ventricular pressure (RVP) and right ventricular dP/dt, has been developed. It consists of a 7F multisensor catheter and an external pacing unit. It allows simultaneous recording of the input signals and the corresponding data can be compared among the different parameters under identical conditions. Furthermore, several parameters can be combined in such a way as to form a new combination better suitable for rate responsive pacing. The response of each parameter to exercise was studied in 12 healthy volunteers (mean age: 28 years). Exercise testing was carried out using a bicycle ergometer, with workloads up to 200 W. The dynamic characteristics, response and sensitivity to changes of workloads of each parameter were analyzed and compared to one another. SO2 proved to be a quick responding parameter (less than 10 sec) with higher sensitivity in the low exercise range (less than 75 W), T, on the other hand, responded slowly (greater than 30 sec) to exercise changes and had the highest sensitivity in the exercise range beyond 75 W. RR displayed a slow response (greater than 30 sec) and an adequate sensitivity was only found in the upper exercise range (greater than 100 W). SV reacted rapidly to workload changes (less than 10 sec) but showed poor sensitivity at all exercise levels. RAP, RVP and dP/dt displayed quick responses and constantly good sensitivity throughout the workload range. Furthermore, respiratory rate was easily derived from the RAP curve. Special algorithms were developed for each parameter so that pacing rate would reproduce sinus rate behavior. We found that SO2 and all pressure parameter imitated sinus rate response quite well. When using parameter combinations, SO2 and T proved to be superior. Five patients (mean age 68 years) with third degree AV-block were stimulated temporarily using this system. Compared to fixed rate stimulation (VVI 70), exercise performance improved, using SO2 as the input parameter for rate response, by 25% to 50%.

Adult↗
PubMed1988

The combined use of hysteresis and Holter functions improves diagnosis and therapy in patients with sick sinus syndrome.

We used the Holter functions of an implantable pacemaker in 12 patients with sino-atrial disease suffering from Adam-Stokes attacks to analyze the effects of hysteresis programming. The basic pacing rate of 50 ppm combined with a programmed hysteresis value of 10 to 20 ppm led to a drastic reduction in competition between paced and spontaneous beats: the percentage of paced beats decreased from 20.1% without hysteresis to 1.4% using 10 ppm hysteresis and the switches from sense to pace decreased from 2.0% to 0.06%. On the other hand, with hysteresis, no decrease in either the exercise tolerance or general well-being of the patients was observed.

Adams-Stokes Syndrome↗
PubMed1988

Analysis accuracy and susceptibility to faults of Holter functions in diagnostic pacemakers.

The analysis accuracy and susceptibility to faults of the additional diagnostic functions were tested in 16 patients (eight men, eight woman, average age 61.5 +/- 10.8 years, 14 VVI, 2 AAI) with diagnostic pacemakers (Quintech DPG 921). The average observation period was 19.7 months. With 109 follow-up intervals of an average duration of 87 +/- 39 days, this meant an observation period of 25.9 patient years. A stage-by-stage test structure over several intervals of time was applied in order to validate the data acquired through pacemaker Holter functions by means of control ECGs and mathematical test methods. The only fault to occur in the diagnostic functions was a loss of stored data. This was observed in 10% of the follow-up intervals and was on the average 28% (16%-38%) of the total events. Forty-four percent (7/16) of the pacemakers were affected by this malfunction. Our results show that the diagnostic data are certainly correctly acquired. The clinical value of the diagnostic functions is clearly reduced by this potential loss of data.

Adult↗
PubMed1988

First clinical experience with an oxygen saturation controlled pacemaker in man.

This article describes the characteristics of a new implantable pacemaker controlled by right atrial oxygen saturation and reports the first clinical experience in man. During the observation period over 5 months, there was no evidence of malfunction due to tissue growth. The system's reaction to exercise changes proved to be quick (5 s to 17 s); decay times varied depending on the magnitude of the power previously performed. Under various exercise tests, the rate increase was linear to the stress load. Measurements of cardiac output showed the system's hemodynamic feedback and its potential self-optimization of pacing rate.

Aged↗
PubMed1988

[Body movement as pacemaker induction value: comparison of 2 activity-triggered pacemakers].

This article compares the rate behavior of the activity-triggered pacemakers, the Activitrax (A) and the Sensolog (S), during bench tests as well as in patients under defined ergometric conditions and during every day life with special reference to the susceptibility of both systems to external noise. In the bench tests both pacemakers were mounted on a swingbord and subjected to controlled vibrational force. In the first experiment the frequency, in the second experiment the energy was varied. In two groups, one with S, one with A implanted, each consisting of 10 patients, the discriminating power of workload changes was examined under defined treadmill exercise. Furthermore in 5 patients of each group the rate behavior of S and A under daily life conditions and during common environmental noise was registered using Holter-ECG. In the bench tests S and A displayed a frequency-selective mode of operation between 2 Hz and 70 Hz with the highest sensitivity (resonance frequency) at 10 Hz. In patients, S showed a significantly higher discriminating power to changes of workload under treadmill exercise. According to y = 0.27x + 85.8 (r = 0.92) the relationship between the pacing rate of S and the power was linear whereas with y = 0.04x + 89.8 (r = 0.2) the pacing rate of A was almost independent of the given power. The susceptibility to external noise occurring during riding a car, streetcar or train with rate increases between 7 ppm and 12 ppm did not significantly differ in both systems.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

[Accuracy of analysis and susceptibility to faults in ECG detection using pacemakers with diagnostic functions].

The accuracy of analysis and susceptibility to faults of additional diagnostic functions in pacemakers were tested in 16 patients (eight men, eight women, average age 61.5 +/- 10.8 years, 14 VVI, 2 AAI) with diagnostic pacemakers (Quintech DPG 921). The average observation period was 19.7 months. With 109 follow-up intervals this meant an observation period of 25.9 patient-years. A stage-by-stage test structure over several periods of time was used in order to validate the data acquired through pacemaker Holter functions by means of control ECGs and mathematical test methods. The only fault to occur in the diagnostic functions was a loss of stored data. This was observed in 10% of follow-up intervals and was, on average, 28% (16-38%) of the total events. 44% (7/16) of the pacemakers were affected by this malfunction. Our results show that the diagnostic data are certainly correctly acquired. The clinical value of the diagnostic functions is clearly reduced by this potential loss of data.

Adult↗
PubMed1988

[Holter functions in cardiac pacemakers: expanding diagnostic possibilities and their clinical relevance].

By encompassing diagnostic multifunctions, microprocessor equipped pulse generators represent a marked improvement in the field of diagnosis and treatment. In this sense, bioelectrical data can be recorded over long periods, up to years, making a continuous follow-up possible. Changes in basic cardiac rhythm, pacemaker malfunctions, effect of parameter programming, even the assessment of antiarrhythmic therapy are some information that could be acquired. The screening function is particularly valuable for detecting sporadic arrhythmias and intermittent pacemaker malfunction which would otherwise go undetected. The limitation of this system lies in the fact that it does not render information on morphology and lacks the chronological correlation between recorded events.

Arrhythmias, Cardiac↗