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Biomedical subjects

H Weidemann

Publications and source records attributed to H Weidemann.

At least 37 records · Page 2Linked to original sources
PubMed1994

Single-photon emission tomography studies of rubidium-81 in the detection of ischaemic heart disease, using a stress-reinjection protocol.

The present study was designed to determine the feasibility of using single-photon emission tomography (SPET) imaging with rubidium-81 (T1/2 = 4.54 h) to detect ischaemic heart disease, using a stress-reinjection protocol and a specially constructed 511-keV hexagonal hole collimator for a standard gamma camera. The diagnostic performance of 81Rb SPET in detecting coronary artery disease (CAD) was investigated in 52 patients with a high prevalence of CAD. Coronary arteriography was performed in 34 patients, 25 of whom were classified as having significant stenosis (> or = 50%). At peak exercise (Cornell protocol), 111-222 MBq 81Rb was injected i.v. for stress imaging, and after 3 h of rest, 74-111 MBq was reinjected for rest imaging. The displayed short- and long-axis slices and the polar map images were interpreted qualitatively. In comparison to coronary arteriography, which served as the gold standard, the performance of 81Rb SPET revealed a sensitivity of 95% for the detection of CAD. Images of diagnostic quality were obtained in all patients, these being comparable to thallium-201 SPET images. In conclusion, these results indicate that the described method can be routinely used for the positron emitter 81Rb with a conventional gamma camera and special shielding. 81Rb has the well-known advantages of a potassium analogue and 81Rb SPET permits better visualization, particularly of the posterior wall of the myocardium, due to the higher photon energy. Considering the typical dose of 201Tl used for SPET (74-148 MBq), a 81Rb SPET scan imposes a significantly lower radiation burden on the patient.

Adult↗
PubMed1994

[Resection with primary anastomosis in complicated diverticulitis. Risk analysis].

107 patients operated for complicated diverticulitis 1988 until 1993 were analysed retrospectively regarding perioperative risk of resection with primary anastomosis (n = 94). 53 of them had peridiverticulitis with stenosis (mortality 0), 41 had emergency operations (mortality 14.6%). Hartmann procedure (n = 13, mortality 7.6%) has been accepted only for the following situations: 1. ileus with secondary damage of the bowel, 2. extended diffuse peritonitis with secondary organ failure, 3. poor blood supply of the bowel, 4. the patient under immunosuppression after transplantation. Regarding these recommendations mortality rate in emergency operations (12.9%) has been lower as compared to 15 to 20% in literature. So regarding the recommendations named above resection with primary anastomosis seems to be a safe procedure in complicated diverticulitis.

Adult↗
PubMed1992

[Circadian variability of rhythm disorders].

Cardiac arrhythmias exhibit also a circadian variability. It is impressingly apparent in sustained ventricular tachycardia and sudden cardiac death. Adrenergic stimulation during morning hours, a physiologic event for the transition from nocturnal to diurnal activity, appears to be an important arrhythmogenic factor (25). The results of the BHAT-study show that beta blocking agents may substantially reduce the risk for sudden cardiac death during morning hours. This notion should thus be considered in treating patients at risk.

Arrhythmias, Cardiac↗
PubMed1992

Major thoracic surgery during long-term extracorporeal lung assist for treatment of severe adult respiratory distress syndrome (ARDS).

Surgery in patients treated with extracorporeal lung assist (ELA) carries a high risk of life threatening bleeding complications caused by the need for systemic anticoagulation. A case report describing a successful surgical intervention for the repair of a broncho-pleural leakage by thoracotomy during ELA is presented. A newly developed heparin coated extracorporeal system was used in a patient being treated for severe adult respiratory distress syndrome (ARDS) after left sided pneumectomy. The heparin coated system allowed discontinuation of systemic heparinization intraoperatively without coagulation complications related to the extracorporeal system. This procedure was followed by resolution of the ARDS.

Adult↗
PubMed1992

Intravascular oxygenation: adjunct in acute respiratory failure.

The IVOX device represents an early prototype of an intravascular membrane oxygenator that is capable of transferring significant amounts of O 2 and CO 2. It employs new hollow-fiber membrane technology and thromboresistant coatings that should allow the development of a membrane oxygenator that can be placed either intravascularly or ex vivo to provide significant gas exchange without the adverse effects seen in prior ECMO studies including bleeding from heparinization and plasma breakthrough resulting in the gradual deterioration of gas exchange. It may well be that this technology will eventually supplant conventional mechanical ventilation in the support of patients requiring intensive ventilator assistance or in those that are long term weaning problems, thus avoiding the not insignificant problems associated with high intensity and/or long term mechanical ventilation.

Animals↗
PubMed1992

[Interval resistance exercise in comparison with bicycle ergometry stress. Studies with resistance endurance training in coronary patients].

UNLABELLED: In the rehabilitation of coronary patients there is an increased interest in using complementary resistance exercise training. Therefore, we studied nine patients (males; age: 51 +/- 7 years) with chronic stable coronary heart disease during extensive resistance exercise (ex RE) (legpress, abduction, adduction) (60-s work: 60-s rest; contraction intensity: 65% of 1 RM) and during intensive resistance exercise (int. RE) (legpress) (30-s work: 45-s rest) with 85% of 1 RM. Non-invasive continuously measured blood pressure, heart rate, norepinephrine, epinephrine, lactic acid, and glucose were compared with values from maximal bicycle ergometry (3-min steps, each 25 w; max. performance: mean 156 w; range 125-200 w). RESULTS: 1) Comparing ex RE and int RE with bicycle ergometry there were no differences in blood pressure (systolic: 206 and 204 vs. 210 mm Hg; ns; diastolic: 98 and 104 vs. 92 mm Hg; ns). Heart rates (104 and 103 vs. 125/min; p < .01), norepinephrine (3.8 and 3.3 vs. 8.8 nmol/l; p < .01) and epinephrine (0.7 and 0.6 vs. 1.4 nmol/l; p < .01) were considerably lower. 2) The most significant increase and decrease of blood pressure and heart rate occurred within 15-30 s after the beginning and end, respectively, of isometric exercise. CONCLUSIONS: 1) ex RE is suitable for patients with stable CHD and cardiac exercise tolerances of 1.5-2 W/kg = 125-150 watts. 2) Blood pressure monitoring by the cuff method (RR) immediately after RE did not reflect blood pressure during RE. 3) Controlling RE by the training heart rate prescribed for endurance exercise is not possible.

Adult↗
PubMed1992

Extracorporeal lung assist with heparin-coated systems.

Extracorporeal lung assist (ELA) has been recommended for the treatment of ARDS if conventional therapy fails. However, the need for nearly complete anticoagulation is a major risk factor for hemorrhagic complications. We describe our experience with 13 ARDS patients treated with ELA using heparin-coated systems (Carmeda). Maintaining partial thromboplastin time and activated clotting time within or close to the normal range, even major surgery (20 thoracotomies and 2 laparotomies) could be performed without undue bleeding complications related to anticoagulation during extracorporeal support. Eight of the 13 patients survived. The use of heparin-coated systems allows prolonged ELA with nearly physiological coagulation function, permitting major surgical intervention. It enhances the safety margin of extracorporeal gas exchange and may ultimately extend its indications.

Adult↗
PubMed1991

[Esophageal diverticula. Clinical aspects and therapy].

18 patients (10 male, 8 female) with an average age of 57 years were operated for diverticula of the esophagus. We found 11 pharyngoesophageal diverticula, 5 parabronchial and 2 epiphrenic diverticula. Major symptoms were dysphagia and regurgitation in pharyngoesophageal diverticula. Dysphagia, substernal pain and hiccough in parabronchial and epiphrenic diverticula. The treatment was resection of diverticula which was combined with myotomy in case of pharyngoesophageal diverticula. 2 patients had severe secondary wound healing. Other postoperative dysfunctions of the esophagus or symptomatic recurrences were not seen.

Aged↗
PubMed1991

[Can the training of coronary patients be monitored by readily measurable parameters?].

The prognosis of coronary patients in terms of the mortality of coronary heart disease shows a positive relation to the severity of clinical and functional diagnostic parameters. Thus exercise therapy should be monitored by criteria that take ischemia, the myocardial situation and rhythm disorders into account. These criteria should be reliable and should be easy to determine as well as to apply. For pragmatic reasons the non-invasive evaluation of findings and the diagnostic symptom-limited ergometer test are especially significant for dosage and monitoring of exercise therapy. Monitored exercise therapy is here understood to mean individually adjusted exercising by patients, and training thus has to be based on diagnostic findings. First existing complaints have to be analyzed and such findings as size of infarction in the ECG, heart volume in the X-ray, size and function of the left ventricle by echography, etc. checked. Afterwards maximum physical work capacity on a multistage bicycle ergometer test is measured with respect to the following termination criteria: a) subjective reports by the patient during exercise (e.g. onset and severity of angina pectoris, dyspnea and/or fatigue of the leg muscles) and b) objective criteria such as significant ischemic ST-depression, exercise-hypertension, age-related submaximal heart rate and significant rhythm disorders. An inverse correlation is found between measured maximum symptom-limited physical performance and the frequency of cardiac termination criteria; a comparable inverse correlation exists with heart volume: max. O2 pulse.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1990

Interval versus continuous exercise training after coronary bypass surgery: a comparison of training-induced acute reactions with respect to the effectiveness of the exercise methods.

In order to improve endurance by exercise on a bicycle ergometer, both the interval method (I) (exertion and recovery phases alternate each minute) and the continuous method (constant exertion) can be employed. We examined the effects of both methods on the following parameters: heart rate, blood pressure, rate-pressure product, glucose, lactate, and catecholamine levels, and physical performance. Two groups of nine male patients were trained daily on a bicycle ergometer for 3.5 weeks. These patients had undergone coronary bypass surgery 24 and/or 26 days before the training started. The training heart rate was set at 86% of the individual maximum heart rate. In the last week of training, the exercise intensity in both patient groups, following either I or C regimen, was 20:121 W and 83 W respectively. The exercise training lasted 20 minutes with the following findings: (1) there were no significant differences in blood pressure, rate-pressure product, rates of glucose and catecholamines, and (2) there was a significantly higher rate of lactate in the second ten minutes of the I training. Before and after the training period, the patients were subjected to a multistage bicycle ergometer exercise test (sitting). The following results obtained after the training favor the I method: (1) patients' physical performance increased (+0.63 vs. +0.26 W/kg; p less than 0.001); (2) heart rate was lower at rest (-9 vs. -4 beats/min; p less than 0.04) and at 75 W (-12 vs. -2 beats/min; p less than 0.02); (3) rate-pressure product was lower at rest (-1675 vs. -291; p less than 0.04) and at 75 W (-2810 vs. -735; p less than 0.05); (4) rate of lactate was lower at 75 W (-0.83 vs. -0.33 mmol/l; p less than 0.04); (5) catecholamines were not lowered by I or C training, and no differences between the two groups could be observed. Exercise training according to the I method involves both the aerobic and anaerobic capacity of the organism, whereas exercise training according to the C method involves only oxidative capacity. After coronary bypass surgery, the I method is better suited to increase physical performance and is more effective in economizing the cardiac function.

Adult↗
PubMed1990

[Acute cardiovascular and metabolic changes in interval and endurance training in selected patients following aortocoronary bypass operation].

UNLABELLED: This study compared the acute changes of cardiovascular and metabolic reactions during interval and continuous training after coronary bypass surgery. Two groups of 9 male patients (age: 59 +/- 4 and 56 +/- 6 years, resp.) each trained on bicycle ergometer start on post-operative days 24 and 26, resp. In both training groups training heart rate was set at 86% of individual maximum heart rate. In the last week of training the exercise intensity in the group of patients who were trained by the continuous method was at 83 watts, and at 20:121 watts in the group of patients who were trained by interval method (rest:work each 1:1 min). At this exercise training that lasted for 20 min the acute response of heart rate, blood pressure, rate-pressure product, glucose, lactate and catecholamines was measured. RESULTS: In both methods there were no significant differences in systolic and diastolic pressure, rate-pressure product, in glucose or catecholamine levels. However, there was a significantly higher rate of lactate in the second 10 min of the interval training. And, in spite of higher peripheral exercise intensity by interval training, there was no higher cardiac work than by the continuous training. These findings suggest that interval training strains the oxidative capacity of the trained muscles in a more intensive and direct way than does continuous training.

Adult↗
PubMed1990

[Effects of interval versus endurance training of increasing performance, cardiovascular function, metabolism and catecholamines in selected patients after aortocoronary bypass operation].

This paper reports the effect of endurance exercise training on bicycle ergometer by interval method (work and interval each 1:1 min) and continuous method on increase of physical performance, decrease of heart rate, rate-pressure-product, glucose, lactate, and catecholamines. Two groups of nine male patients (aged 59 +/- 4 vs 56 +/- 6 (mean +/- SD)) after coronary bypass surgery each participated in the inpatient rehabilitation training. Training started 24 and 26 days, resp., after surgery and lasted for 3.5 weeks. Frequency and duration of exercise training: Monday-Friday 1 x 20 min and 1 x 25 min per day; Saturday/Sunday each 1 x 25 min per day. In the interval group and the continuous group the exercise training intensity was set at 86% of individual max. heart rate. In the last week of training mean exercise intensity was at 83 watts in the group of patients who were trained by the continuous method and at 20:121 watts in the group of patients who were trained by the interval method. Before and after the training period patients underwent a multistage bicycle ergometer exercise test in sitting position. Beginning at 25 w, each stage was increased by 25 w, whereby each stage lasted 3 min. Cutoff criteria were heart rate (220 - age x 0.85) and/or fatigue of the leg muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Increased plasma level of atrial natriuretic peptide in patients with stress-induced coronary insufficiency: stretch-independent release of atrial natriuretic peptide?].

Plasma levels of atrial natriuretic peptide (ANP) were determined in 34 male patients undergoing diagnostic right heart catheterization. Patients with effort angina exhibited significant higher ANP levels at rest (259 +/- 42 pg/ml; n = 7) than patients without signs of coronary heart disease (78 +/- 30 pg/ml; n = 8). Patients with effort angina also had higher ANP levels at rest than patients exhibiting impaired cardiac function on exertion without signs of ischemia (105 +/- 15 pg/ml; n = 4), patients with only minimal functional alterations due to infarction residues (95 +/- 27 pg/ml; n = 7), or patients with only borderline changes of ST-segments during exertion (61 +/- 19 pg/ml; n = 8). In contrast, mean pulmonary capillary or right atrial pressures were not significantly different between the various groups of patients. The patients with effort angina also exhibited the highest ANP levels during bicycle exercise (846 +/- 238 pg/ml). There was only a weak to moderate linear correlation between ANP levels and pulmonary or right atrial pressures in the whole group of patients (r = 0.1-0.6). The plasma levels of epinephrine and norepinephrine and of ANP were not significantly correlated, with the exception of norepinephrine levels during exercise (r = 0.54). Our observations suggest that in patients with effort angina there may exist additional stretch-independent factors stimulating the release of ANP, possibly associated with repetitive myocardial ischemia.

Angina Pectoris↗
PubMed1990

[Seroprevalence of human parvovirus B 19 antibodies (Sticker's disease/erythema infectiosum) in the DRG population].

We tested 638 human sera of all age groups (patients and blood donors) from the northern area of the G.D.R. and found 216 cases (33.9%) of specific parvovirus B19 antibodies (IgG) by antibody capture ELISA. The seroprevalence rose to 36.7% when the 18 parvo B19-IgM- and/or parvo B19-DNA-positive results were included. The antibody prevalence was 24.9 (27.8% resp.) in the 0-10 years group and increased continuously in the following age groups up to 61.1% (69.4% resp.) in the 51-60 years group. 50% of the newborn infants showed parvo B19-IgG-antibodies in the cord blood (of maternal origin). No sex differences in seroprevalence were observed. Parvovirus B19 is obviously very prevalent in the G.D.R. population. The main immunization occurs in the first 30-40 years of life but infection with parvo B19 at a later age is also well documented. Hence it follows that 35-45% of all G.D.R. females of reproductive age are susceptible to a parvovirus B19 infection.

Adolescent↗