Biomedical subjects

U J Winter

Publications and source records attributed to U J Winter.

26 records · Page 2Linked to original sources

PubMed1993

[Effect of a single blood donation on ergo-spirometrically determined cardiopulmonary performance capacity of young healthy probands].

Autologous blood donation is an established method for an effective reduction of the blood-transfusion-associated infectious diseases (hepatitis, HIV infections, etc.) in elective surgical procedures. The aim of the study was to investigate the effects of a blood donation of 450 ml on the cardiopulmonary exercise capacity in 16 apparently healthy young subjects. The 24 cardiopulmonary exercise tests were performed on a bicycle ergometer (Ergoline 900) in a semisupine position, using a ramp program (+20 watt/min) 1-7 days before and 2 days after blood donation. By means of continuous breath-by-breath measurements of the gas exchange (VO2, VCO2) and ventilation parameters (minute ventilation VE), as well as of the routine parameters (heart rate, blood pressure, work rate) during incremental exercise the respiratory anaerobic threshold VO2AT, the maximum VO2 (VO2max and the maximal working capacity (max. WR) were determined. Serum hemoglobin concentration was significantly (p < 0.0005) reduced from 14.5 +/- 1.0 to 13.0 +/- 1.4 g/dl after blood donation. The ventilatory anaerobic threshold (before: 68.5 +/- 17.0; after: 52.0 +/- 20.3% pred. max. VO2), the max. VO2 (before: 124.2 +/- 21.3; after: 110.2 +/- 23.2% pred. max. VO2) and max. WR (before: 287.1 +/- 75.6; after 265.5 +/- 76.2 watt) fell significantly (VO2AT: p < 0.0005; max. VO2: p < 0.0005; max. WR: p < 0.025). Heart rate and minute ventilation showed a steeper increase (dHR/dWR: before: 0.31 +/- 0.06; after: 0.34 +/- 0.05 beats/min/watt; dVE/dWR: before: 0.29 +/- 0.05; after: 0.31 +/- 0.05 l/watt) in relation to the increase in WR after blood donation as compared to the test before.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Local vascular complications in heart catheter studies].

Over a period of 30 months (1. 1. 89-30. 6. 91) 3516 patients who had either a diagnostic (2718) or therapeutic (798) heart catheterization were followed for local vascular complications. 774 patients were investigated prospectively. The following complications were observed in declining frequency: 1. relevant haematoma, 2. pseudoaneurysm, 3. arteriovenous fistula, 4. arterial thrombosis/dissection, 5. venous thrombosis, 6. rupture of the vessel, 7. local infection. The total complication rate was 2.22%. With prospective investigation it was significantly higher (3.23%) than with retrospective investigation (1.93%). The complication rate was also significantly higher in therapeutical procedures (3.76%) than in diagnostic catheterizations (1.76%). Factors associated with a significantly higher incidence of local vascular complications were age (p < 0.01), female gender (p < 0.025), manifest arterial hypertension (p < 0.005), aortic regurgitation (p < 0.1), peri-interventional medication with acetylsalicylic acid and full dose heparin (p < 0.001), full dose heparin alone (p < 0.001) or fibrinolysis-therapy (p < 0.025). Relevant technical factors were: duration of the procedure, duration of the placement of the catheter-sheath, French size of the catheter, left femoral access, arterial and venous access at one extremity. In about half of the cases the treatment of the complications was conservative, in the other half it was surgical (51%). In relation to all surgically treated patients the percentage of emergency operations was 25%, the percentage of reoperations was 15%.

Adult↗

PubMed1991

Cardiopulmonary exercise testing (CPX) and transthoracic bioimpedance measurements: new tools for an "old disease" (congestive heart failure).

The purpose of the study was to examine the cardiovascular and cardiopulmonary exercise capacity in patients with symptomatic congestive heart failure more exactly than with conventional investigations, using the simultaneous non-invasive determination of the gas exchange parameters (ergospirometry, CPX) and of the hemodynamic (transthoracic bioimpedance). The reproducibility of the data were measured with each method with repeated tests under the same conditions in healthy subjects and patients with myocardial failure. Therefore we tested 15 patients with documented congestive heart failure repeatedly on a bicycle (semi-supine, +15 watts/min, symptom-limited). The ergospirometric (VO2, VCO2, RER = VCO2/VO2, max. VO2, VO2AT, VE, RR) and the bioimpedance-parameters (CI, SVI, HR) were measured simultaneously during rest and exercise. According to Wasserman et al. we used the VO2AT and the max. VO2 to assign the patients to the different Weber classes: Weber A: greater than 20 ml/min/kg max. VO2, greater than 14 ml/min/kg VO2AT; Weber B: 16 to 20 ml/min/kg max. VO2, 11 to 14 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. ml/min/kg VO2AT; Weber C: 10 to 16 ml/min/kg max. VO2, 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. VO2, 4 to 8 ml/min/kg VO2AT: Weber E: less than 6 ml/min/kg max. VO2, less than 4 ml/min/kg VO2AT. The V-slope-method according to Beaver et al. allowed for the determination of the anaerobic threshold in 13/15 patients. 2/15 patients didn't reach the anaerobic threshold. Oscillations of the gas exchange parameters due to Cheyne-Stokes-breathing were found in 9/15 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Effect of different body-exercise modes on the rate response of the temperature-controlled pacemaker Nova MR.

In order to evaluate the effect of different modes of physical exercise on the rate response of the temperature-controlled Nova MR, parameters such as temperature behaviour and correlation of work load to pacing rate were investigated using different types and protocols of stress testing. This study considered 21 patients (age: 66 +/- 12 y). The indications for the Nova MR were AV block (n: 14) and sick sinus syndrome (n: 7). The patients performed two different types of exercise (treadmill n: 13, bicycle n: 14) based on different protocols. We registered the surface ECG, pacing rate, exercise time, and (via data transmission by the RX 2000 programmer) blood temperature and pacing rate. An adequate rate response could be achieved with all the different types of exercise and protocols using more sensitive program settings. The type of stress testing used to adjust or evaluate the Nova MR seems to be secondary, although cycling as compared with treadmill exercise resulted in a slightly weakened reaction of temperature and pacing rate. Our investigations revealed a good correlation between work load and pacing rate independent of the type of stress testing. The initial DIP (48%) is not a constant phenomenon and showed inter- and intraindividual variations. Impressive psychological influences also exhibited an effect on temperature and pacing rate, sometimes preventing a DIP response. During exercise at lower work loads (under 50 watts, shorter than 3-4 min) the rate response of the Nova MR--without any detected DIP--is often delayed due either to a decrease or to a late and flat increase in temperature. An additional fast-reacting sensor could be advantageous in triggering the initial rate response in such cases.

Aged↗

PubMed1987

[Activity-initiated rate-adapted pacemaker therapy. Clinical results].

In a prospective study of 23 patients the clinical effects of rate-adapted activity-sensed (by mechanical resonance oscillations) pacing (Activitrax system) were tested over a mean period of 8.1 +/- 3.8 months. This form of pacemaker treatment was used when, after exercise and on long-term ECG monitoring, the spontaneous heart rate had not exceeded 85 beats per min and there had been symptoms of decreased exercise tolerance. Lasting improvement in physical exercise tolerance was achieved in 11 of 17 patients after changing from fixed-rate to rate-adapted pacing. Treadmill ergometry, randomised in the fixed-rate or rate-adapted mode, brought about a significant rise in exercise tolerance (P greater than 0.01). Contrary to results after external influences, insufficient rate increases in five patients in the course of static stress was of clinical significance and thus narrow the indications for this type of pacing.

Adult↗

PubMed1986

[Treatment of hydrofluoric acid burns].

A chemical-plant worker sustained hydrofluoric acid burns during cleaning procedures. Intra-arterial perfusion and intralesional injections of calcium gluconate solution prevented progression of the burns into deeper tissue layers.

Accidents, Occupational↗

PubMed1986

Noninvasive control of the early postimplantation period.

Modern programmable pacemakers often incorporate features that allow one to perform a series of diagnostic maneuvers to aid in postimplantation surveillance. These features often include noninvasive measurements of thresholds, lead impedance, and intracardiac electrogram recognition via telemetry circuits. Interindividual differences in these measurements are so great that one must utilize individual comparisons for longitudinal studies of reliability. While these devices allow "fine tuning" of individual units, they require major time-consuming efforts and add to the total device costs.

Adult↗

PubMed1982

[Continuous registration of micropotentials of the human heart. Initial experiences with a new high resolution ECG amplifier system].

A new ECG-amplifier system for recording cardiac microvolt potentials from the body surface is described. The improvement in signal-to-noise ratio was achieved by using specially designed suction electrodes, which were isolated from each other; by applying parallel signal averaging from four electrode pairs via four low-noise amplifiers; and by conducting the registration in Faraday cage. in 14 normal subjects, 12 patients with coronary heart disease and one patient with surgically corrected ventricular septal defect and pulmonary stenosis, pre-P-potentials (possible sinus node activity), His bundle potentials and ventricular late potentials were recorded with differing degrees of success. Variations of the time intervals to the preceding QRS complex were observed within the S-T segment in six of nine patients with demonstrable ventricular late ventricular late potentials. The advantage of such continuously recording ECG system lies in the highly accurate registration of cardiac micropotentials, particularly with ventricular late potentials that are changing in time, whereas the signal-averaging technique does not provide such possibilities.

Adolescent↗