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Biomedical subjects

W D Bussmann

Publications and source records attributed to W D Bussmann.

At least 19 recordsLinked to original sources

[Effect of prazosin in therapy-resistant chronic cardiac failure (author's transl)].

In addition to standard treatment with digitalis and diuretics prazosin (20 mg/d) and placebo were given to 14 patients with chronic therapy-resistant cardiac failure mainly of stage III for periods of 6 weeks each. Cardiac frequency, blood pressure, cardiac volume, pulmonary artery pressures and cardiac minute volume were assessed at rest and during physical exercise. Body weight, congestive changes in the chest radiograph, oedema and complaints were evaluated. During the acute trial using 2 mg of prazosin a significant increase of cardiac minute volume was demonstrable at rest and during exercise (2 P less than 0.05). After administration for 6 weeks cardiac minute volume increased from 3.2 to 4.0 l/min at rest and from 6.9 to 8.0 l/min during exercise (2P less than 0.005; n=12). There was a noticeable decrease of cardiac size from 1440 to 1306 ml/1.73 m2 (2 P less than 0.02). Haemodynamic improvement paralleled the decrease of complaints which was equivalent to an improvement of half to one stage of the New York Heart Association. In severe cardiac failure prazosin has thus an additional therapeutic effect beyond digitalis and diuretics.

Adult

[IX. Randomized study of the effect of nitroglycerin on CK and CK-MB infarct size. Preliminary report (author's transl)].

In 38 patients with acute myocardial infarction the effect of nitroglycerin on infarct size was studied. Patients were randomized into two groups. 16 patients received continuous nitroglycerin infusions of 0.6 to 6.0 mg/h (mean 2.3 mg/h) over a 48 h period, 22 patients received no specific therapy and served as control. Nitroglycerin was given in the mean 12 +/- 5 (+/- 1 SD) hours following onset of chest pain and 8 +/- 5 after the increase of CK values. Infarct size was determined according to the time activity curve of creatine kinase (CK) and of its myocardial isoenzyme (CK-MB). In all but one patient hemodynamic parameters (left ventricular filling pressure, blood pressure, cardiac index) were measured. The mean infarct size was 51 +/- 30 CK-g-equiv. in control patients, and 48 +/- 33 g in nitroglycerin treated patients. Infarct size as calculated from CK-MB values was 60 +/- 36 g (n=16) in control, and 52 +/- 41 g (n=11) in treated patients. At left ventricular filling pressure values (LVFP) below 20mm Hg infarct size amounted to 43 +/- 30 g (n=12) in control, and to 41 +/- 32 g (n=11) in the nitroglycerin group. At LVFP values above 20 mmHg infarct size was 61 +/- 29 g (n=10) in control as opposed to 64 +/- 32 g (n=5) in treated patients. There was no difference between infarct size as predicted during the first 7 h and the observed infarct size. - Despite the known beneficial effect of nitroglycerin on hemodynamics and on myocardial ischemia, infarct size seems not to be greatly reduced, however, intervention occurred fairly late (12 h). In early intervention beneficfial effects seem likely.

Adult

[Comparison of bicycle ergometry and step-ladder exercise (author's transl)].

Repeat exercises (three hours apart) on a bicycle ergometer and a vertical step-ladder were performed in a randomised series on 79 subjects: 13 doctors, 44 patients and 22 sportsmen. Duration of exercise was on average 250% longer in the three groups on the step-ladder than the bicycle. Correspondingly, exercise-pulse sums, recovery-pulse sums and exercise indices were two-and-a-half to three times higher than on bicycle ergometry. As a sign of comparability of the exercise by the two methods there was, on average, no significant difference with regard to the final heart rate, although duration of exercise was longer on the step-ladder. 67% of subjects discontinued the exercise because of peripheral muscle fatigue on the bicycle ergometer, compared with only 8% on the step-ladder. During bicycle ergometry lactate concentration rose by 6.7 mmol/l compared with only 0.78 mmol/l during step-ladder exercise. These results indicate that the value of bicycle ergometry exercise is limited by muscle fatigue in the legs: step-ladder exercise can be extended much longer. The practical significance is that patients with coronary heart disease especially have symptoms and/or ECG changes of ischaemia only at higher levels of physical exercise.

Adolescent

Nitroglycerin in acute myocardial infarction. X. Effect of small and large doses of nitroglycerin on sigma ST segment deviation -- experimental and clinical results.

The purpose of the present study was to investigate the effect of the dose of nitroglycerin (NTG) on myocardial ischemic injury. In 20 closed chest dogs the anterior descending branch of the left coronary artery was occluded by inflating a balloon in its lumen. Compared with the untreated control group the sigma ST elevation was significantly lower when NTG was applied at a rate of 0.02 mg/min, but significantly higher when NTG was administered at a rate of 0.10 mg/min. In 12 patients with acute myocardial infarction NTG was infused at a rate of 3 mg in the first hour (0.05 mg/min) and 6 mg in the second hour (0.1 mg/min). Sigma ST elevation and sigma ST depression decreased during the lower infusion rate (p less than 0.001). When the rate of NTG infusion was raised to 6 mg/hr, the improvement in ST segment deviation was partially reversed. This effect, particularly evident in patients not in heart failure, was associated with a significant rise in heart rate (p less than 0.05) and a fall in diastolic arterial pressure (p less than 0.025). Patients with left ventricular failure were less sensitive to higher doses of NTG than those without failure. Thus, the effect of NTG on myocardial ischemic injury depends on the NTG dose and on the functional state of the injured left ventricle.

Animals

Treatment of hypertrophic obstructive cardiomyopathy with verapamil.

Twenty-two patients with hypertrophic obstructive cardiomyopathy were treated with the calcium inhibitor, verapamil, which was administered in a mean oral dose of 480 mg per day. After an average of 15 months of treatment (4 to 24 months), the QRS amplitude in the electrocardiogram was significantly reduced from 4.2 to 3.8 mV. Heart volume calculated from chest x-ray films in the supine position decreased significantly from 858 to 766 ml per 1.73 m2. In 10 patients, follow-up heart catheterisation showed a decrease in left ventricular muscle mass in 7 patients and a slight increase in 3 patients. Coronary artery diameter decreased in 7 patients, increased in 1, and was unchanged in 2. The reduction in coronary artery diameter is considered to be a consequence of a reduced heart muscle mass. From all available clinical data it is concluded that verapamil treatment is superior to beta-blocker therapy.

Adult

[Regional ventricular function at rest during exercise before and after bypass surgery (author's transl)].

In 9 patients with coronary heart disease isovolumetric contractility indices and ejection phase parameters were measured simultaneously, using an angiographic catheter with a manometer at the tip (Millar). Regional wall motion at rest, after leg raising and during physical exercise (bicycle ergometer) was analyzed applying the hemiaxis method. Five weeks after aortocoronary bypass surgery the same examinations were repeated. Preoperatively left ventricular enddiastolic pressure (LVEDP) increased from 21 to 37 mm Hg following leg raising. The velocity mean of fiber shortening (Vcf) and of regional fiber shortening in the anterior wall decreased significantly.--All patients discontinued physical exercise due to angina pectoris. LVEDP increased from 21 to 39 mm Hg. Large hypokinetic and akinetic areas developed especially in the anterior wall. Velocity of fiber shortening of the anterior wall decreased from 1.43 to 0.76/s. Enddiastolic volume remained unchanged while endsystolic volume increased significantly. In six patients with patent grafts surgery had a beneficial effect. Comparing angiograms at rest no significant changes were found. After leg raising and physical exercise, however, marked improvement in ventricular function occurred, compared to the preoperative performance. All 6 patients were exercised without complaints at a load of 100 watts for 8 minutes. Velocity of fiber shortening in the anterior wall increased significantly from 0.76 to 2.56/s, mean Vcf from 1.11 to 2.12 circ/s, max dP/dt from 2302 to 4280 mm Hg/s and Vpm from 27.8 to 55.7/s. Functional improvement in individual wall segments amounted to 500% in the mean. Ejection fraction increased from 54 to 76%. Enddiastolic volume remained unchanged while endsystolic volume decreased from 67 to 33 ml/1.37 m2 (p less than 0.002). In three patients the bypass occluded or myocardial infarction occurred intraoperatively. Postoperative findings at rest and during exercise were unchanged as compared to preoperative values. Following successful bypass surgery ventricular function at rest did not change. During exercise, however, a marked improvement in overall and in regional ventricular function was found.

Angiocardiography

[Contractile and relaxation reserve of the left ventricle. III. Patients with cardiomyopathy (author's transl)].

Seven of 22 patients with cardiomyopathy increased maximal rate of left ventricular pressure rise (max dP/dt) above 3200 mm Hg/s and dP/dt/P above 60/s. Relaxation reserve was normal with an increase of min dP/dt above 2400 mm Hg/s.--In 15 patients contractile and relaxation reserve was reduced. In congestive cardiomyopathy, contractility and relaxation reserve were equally reduced. Left ventricular enddiastolic pressure increased during exercise slightly or not (grade 1). Enddiastolic volume was elevated to 173 +/- 50 ml/1.73 m2 and endsystolic volume to 63 +/- 22 ml/1.73 m2; ejection fraction and mean circumferential fiber shortening were reduced (61 +/- 17%; 1.3 +/- 0.9 circ/s). In hypertrophic cardiomyopathy without obstruction, contractile and relaxation reserve and ejection phase parameters could be found to be normal. Enddiastolic pressure at rest was elevated. In severe cases, contractile and relaxation reserve were markedly reduced and enddiastolic pressure increased to a greater extent than in congestive cardiomyopathy. In addition, relaxation reserve was reduced, especially in patients with excessive hypertrophy of the myocardium. These had abnormal (grade 2) and pathological reaction to exercise: contractile and relaxation reserve were decreased and enddiastolic pressure (grade 3) increased. Left ventricular contractility was found to be almost normal in patients with hypertrophic obstructive cardiomyopathy. This was the case despite increases in enddiastolic pressure. Contractile reserve was reduced, however, in patients with excessive hypertrophy. Diastolic filling was impeded during exercise.--Measuring left ventricular function during exercise, different types of cardiomyopathy correlate with typical hemodynamic alterations.

Adult