Biomedical subjects
Publications and source records attributed to W Angehrn.
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The effect of nitroglycerin ointment (30 mg) and isosorbide dinitrate ointment (100 mg) versus placebo on exercise capacity has been investigated in 12 patients. All had angina pectoris and coronary artery disease documented by coronary angiography. Nitroglycerin and isosorbide dinitrate ointment produced a significant increase in exercise capacity, without any significant difference in the beneficial effect of the two. Stress-induced changes of the ST-segment in the electrocardiogram decreased by 65% after nitroglycerin ointment and by 41% after isosorbide dinitrate ointment, compared to placebo. These results indicate that nitroglycerin and isosorbide dinitrate ointment reduce stress-induced myocardial ischemia at similar work loads.
The effect of phentolamine was studied in 5 patients with pulmonary hypertension, of whom 3 had primary pulmonary hypertension and 2 had secondary pulmonary hypertension after pulmonary embolism. They received intravenous phentolamine in doses of 0.5 mg/min to 2 mg/min (i.e. up to a total dose of 27.5 mg in 25 minutes) during diagnostic cardiac catheterization. Under phentolamine infusion only 2 of the 3 patients with primary pulmonary hypertension showed a significant rise in cardiac index, from 1.4 to 2.0 and from 1.8 to 2.2 l/min/m2 respectively, a fall in pulmonary artery mean pressure from 100 to 93 and from 42 to 33 mm Hg respectively, and a decrease in pulmonary vascular resistance from 2950 to 1900 and from 1160 to 725 dyn X sec X cm-5 respectively. In 1 patient with primary, and 2 patients with secondary pulmonary hypertension, infusion of phentolamine had no effect. Interestingly, in the two patients with primary pulmonary hypertension who responded well to phentolamine the condition was very severe. It appears that even in cases with very advanced primary pulmonary hypertension there is a vasospastic component which can be influenced by vasodilators.
More than 40% of patients hospitalized in the Wald Altitude Clinic of Zürich are already on long-term digitalis therapy upon admission. During a 6 month period long-term digoxin therapy was discontinued in 97 patients (age 74 +/- 9 years) with stable cardiac insufficiency (NYHA class I-III) and sinus rhythm. During the hospitalization (37 +/- 20 days), clinical signs and symptoms, body weight, radiological heart size, and systolic time intervals were monitored. After an observation period of one week, digoxin was discontinued in all patients. Body weight, cardio-thoracic ratio and left ventricular ejection time remained unchanged after cessation of digoxin therapy during hospitalization. The pre-ejection period showed a significant increase from 89 +/- 17 to 95 +/- 19 msec. Six patients were re-instituted on digoxin therapy, 3 due to progressive cardiac insufficiency, 2 due to atrial fibrillation, and 1 at his own request. After telephone follow-up six months later with the family physician an additional 20 patients were put back on digitalis. Among the total of 26 patients requiring further digitalization an absolute indication was found only in 12 (14%), 8 due to progressive cardiac insufficiency and 4 due to atrial fibrillation. In this study digitalis therapy could be discontinued without ill effects in 86% of elderly clinically stable patients in sinus rhythm. The authors therefore recommend a more cautious use of long-term digitalis therapy and, in already digitalized patients in sinus rhythm, a controlled trial period of discontinuation.
Cautious estimates reveal that the diagnosis of pulmonary embolism is missed in approximately 60-70% of cases. The outcome in these patients is poor, mainly due to a tendency to relapsing embolism. Knowledge of pathophysiological contexts is important for clinical diagnosis and for evaluating degree of embolism. In most cases consistent conservative treatment is sufficient. Emergency embolectomy is indicated in cases with severe central pulmonary embolism. Operation mortality has dropped considerably since the introduction of cardiopulmonary bypass.
Hepatosplanchnic blood flow (EHBF) was estimated with the single-injection method using indocyanine green in 10 patients without cardiac failure before and after 20 min of an intravenous infusion of dopamine. Five patients received 4 microgram/kg/min and another 5 patients 8 microgram/kg/min. The cardiac index (CI) was determined according to the Fick principle, and the arterio-hepatovenous oxygen difference (AV DO2 AO/HV) was measured. The mean increase in EHBF in the 10 patients was from 640 +/- 46 ml/min/m2 to 831 +/- 56 ml/min/m2 (p less than 0.001). The percentage of EHBF to CI increased from 24.1 +/- 2.0% to 26.4 +/- 1.6% (p less than 0.05). The mean AV DO2 AO/HV dropped from 49.6 +/- 3.8 ml/liter to 40.4+/- 2.9 ml/liter (p less than 0.005). We conclude that dopamine given at rates of 4 and 8 microgram/kg/min to patients whose hearts are well compensated increases hepatosplanchnic flow. Thus, the large increase in renal blood flow which occurs with dopamine is not at the expense of hepatosplanchnic blood flow.
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1. Voluntary hyperventilation during rest in the recumbent position induces a fall in H+ concentration, PCO2 and PO2 in mixed venous blood and in the blood of the coronary sinus. 2. If the breathing volume is increased during voluntary hyperventilation between 2- and 2.5 fold above the volume at rest, O2 uptake increases by only 6% but CO2 excretion rises by 66%. 3. Cardiac output decreases by 8% and the O2 extraction of the myocard increases by 12%. There is a quantitative relationship between arterial pH or PCO2 and changes in the systemic and coronary circulation. Blood pressure decreases in the pulmonary circulation. 4. Nitroglycerin during hyperventilation produces an additional reduction in cardiac output but no effect on the O2 extractions of the myocard. 5. With dipyridamol, the O2 extraction of the myocard is reduced and the PO2 in the blood of the coronary sinus increases. 6. In the case of severe coronary obstruction, the effect of dipyridamol can cause acute angina pectoris and left heart insufficiency due to poststenotic ischemis (steal syndrome).
Dopamine (3,4 dihydroxyphenylethylamine) increases cardiac output and in particular the renal blood flow at the expense of other regional vascular beds not yet defined. Since the results of dopamine-induced changes in splanchnic perfusion are inconsistent, the effect of 6 mcg/kg/min dopamine was studied in 9 patients early after open heart surgery. Estimated hepatic blood flow (EHBF) was calculated from the concentration-time slopes of Indocyanine Green (ICG, Cardiogreen) in arterial and hepatic venous blood following single intravenous injection. Blood volume was measured using 51Cr tagged red cells. Cardiac output was determined according to the Fick method. 6 mcg/kg/min dopamine caused a mean EHBF-increase of 82%, from 492 +/- 64 to 824 +/- 80 ml/min/m2 (P less than 0.001). Related to the corresponding increase in cardiac index (CI) from 2.6 +/- 0.2 to 3.8 +/- 0.3 1/min/m2 (P less than 0.001), the EHBF/CI-ratio changed from 18.5 to 21.7% (P less than 0.025). The arterial-hepatic venous oxygen difference was reduced from 7.40 +/- 0.53 to 4.91 +/- 0.60 Vol% (P less than 0.001). It was concluded that splanchnic perfusion does not contribute to the preferential increase of renal blood flow under dopamine under the above mentioned conditions. Dopamine had the most beneficial effect on EHBF in two cases where the latter was severely reduced.
From 1970 to 1977 the diagnosis of hypertrophic, nonobstructive cardiomyopathy was made by clinical, echocardiographic and hemodynamic findings in 13 patients (2 females and 11 males). Echocardiography showed asymmetric septal hypertrophy in 10 of the 12 evaluated patients (83%) and symmetric hypertrophy of the septum and the posterior wall in 2 patients (17%). Systolic anterior motion of the anterior mitral leaflet was found in 5 patients (42%) although there was no obstruction of the outflow tract. Significantly higher angiographic ejection parameters were present in the 13 patients with cardiomyopathy compared to 13 control patients and the angiographic lateral wall thickness was significantly larger in patients with cardiomyopathy than in controls. The clinical course was followed during 36 mth; a stable course was found in 8 (group A) and a deterioration in 5 patients (group B). Physical working capacity and left ventricular systolic ejection fraction were significantly higher in group A than in group B. Ejection fraction in group B was similar to that of the controls whereas physical working capacity was depressed. Thus, in nonobstructive cardiomyopathy a higher than normal ejection fraction is needed to maintain a normal physical working capacity. Th increased ejection performance seems, however, not to be related to an increase in muscle fiber shortening, but can be explained by geometric reasons.
1. Voluntary hyperventilation during rest and in the recumbent position induces a fall in H+ concentration, PCO2 and PO2 in mixed venous blood and in the blood of the coronary sinus. 2. In 7 of 12 patients the arterio-venous O2 difference increased by more than 10% of the control value (mean increase 21%). At the same time the O2 extraction of the myocard increased (mean increase 17%) in these subjects. Blood pressure and pulse rate varied only slightly in these experiments. 3. Chest pain and angina pectoris due to hyperventilation are the result of impaired myocardial O2 supply, a finding which is valid for subjects with and without coronary heart disease.
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Intravenous dopamine (4 and 8 microgram/kg/min) causes an increase of hepatic flow and cardiac index, while the ratio hepatic flow:cardiac index remains unchanged. The increase of renal flow after dopamine therefore does not occur at the expense of hepatic flow.
Survival rate and incidence of myocardial infarction after aortocoronary bypass operation in 274 patients are presented. Mortality was 5.1% within the first postoperative month and the 5-year-survival rate was 86%. There were 24 perioperative myocardial infarctions and another 21 infarctions over the next 5 years. Comparison of these data with the natural history of coronary heart disease suggests a possible prolongation of survival after bypass surgery. The incidence of myocardial infarction appears to be unchanged.
Left ventricular enddiastolic pressure (LVEDP) was studied during exercise in 22 patients pre- and postoperatively under an identical work load. 13 patients showed improvement of LVEDP (normalization in 5), LVEDP was unchanged in 5 (w.n.l. in 2), and had deteriorated in 4. These results suggest that improvement or normalization of LVEDP under exercise following aortocoronary bypass surgery can be assumed if there is complete revascularization, if all grafts are functioning well, if there is no progression of the underlying disease, and if preoperative LV angiography is normal or shows only ischemic (reversible) hypokinesis.
The sick sinus syndrome (SSS) is a complex cardiac disturbance involving impulse formation and conduction. Anatomy and physiology of the sinus node and atrial conduction are reviewed and the pathophysiology of bradycardia and tachycardia in the SSS is discussed. Finally, a practical approach to diagnosis is outlined.
Case report on successful open heart surgery in a 21-year-old male with cor triatriatum.
In a 66-year-old woman with suspected cholecystopathy, cholecystectomy led to the chance finding of the common liver fluke Fasciola hepatica (F.h.) in the common bile duct. Subsequent therapy with Dehydroemetin brought about regression of eosinophilia and of the pathologic immunofluorescent antibody test for F.h. The life cycle of F.h. and the clinical features of human infection are described in detail.