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Biomedical subjects

O Bertel

Publications and source records attributed to O Bertel.

At least 127 records · Page 7Linked to original sources

Plasma adrenaline and noradrenaline in patients with acute myocardial infarction. Relationship to ventricular arrhythmias of varying severity.

Plasma adrenaline (A) and noradrenaline concentrations (NA) were determined in 41 patients admitted to the coronary care unit (CCU). Eleven with suspected acute myocardial infarction (AMI), subsequently excluded as a diagnosis, had significantly elevated A and NA compared with 20 normal resting subjects. Patients with proven infarcts but no ventricular fibrillation had even higher levels of A and NA. Nine patients with ventricular fibrillation as a complication of AMI showed the highest plasma catecholamine values on admission. Patients with AMI and congestive heart failure exhibited substantially increased A, while NA was only slightly elevated compared with that of AMI patients without congestive heart failure. High plasma catecholamines and the relationship between adrenaline and the severity of ventricular arrhythmias suggest that the sympathetic nervous system plays an important role in sustaining a vicious circle of increased myocardial damage and increased irritability during the acute phase of AMI.

Adult↗

An oral calcium antagonist for treatment of hypertensive emergencies.

The efficacy and safety of 20 mg of nifedipine as a single oral dose have been studied with respect to the use of the drug as an alternative treatment of hypertensive emergencies. The study population consisted of nine male and nine female patients, 47 to 80 years old. The mean systolic blood pressure decreased from 220 +/- 22 to 150 +/- 21 mm Hg and the mean diastolic blood pressure from 122 +/- 11 to 86 +/- 10 mm Hg (p less than 0.001) within 20-30 min. The decrease of blood pressure was paralleled by a small but significant increase (p less than 0.01) in heart rate from 74 +/- 9 to 85 +/- 10 beats/min. The fall of blood pressure was directly related to pretreatment values. Oral nifedipine can be recommended as a first-line drug to lower blood pressure in hypertensive emergencies.

Aged↗

Sustained effectiveness of chronic prazosin therapy in severe chronic congestive heart failure.

Twelve patients with severe chronic congestive heart failure (CHF) (NYHA class III and IV) resistant to digitalis and diuretics were treated with the postsynaptic alpha-blocking agent prazosin (PZ) (3 to 20 mg/day). In 11 patients oral PZ treatment was well tolerated; the agent was discontinued in the remaining patient because of orthostatic dizziness. After 4 weeks of PZ, total systemic vascular resistance decreased from 2245 +/- 792 to 1603 +/- 355 dyn sec cm-5, mean blood pressure declined from 100 +/- 15 to 90 +/- 14 mm Hg, and pulmonary capillary wedge pressure decreased from 29 +/- 8 to 25 +/- 9 mm Hg. Cardiac index increased from 1.92 +/- 0.63 to 2.30 +/- 0.41 l/min/m2. The increase of stroke volume index correlated with the fall in peripheral vascular resistance (r = --0.79, p less than 0.01) and the decline in pulmonary capillary wedge pressure (r = --0.75, p less than 0.05). In parallel, exercise tolerance increased significantly. Four patients improved from functional class IV to II, four from class IV to III, and one from class III to II, while two patients were unchanged. In the eight patients followed for 6 months, the beneficial effects of ambulatory PZ were maintained throughout the expansive observation period. Three patients died as their disease process progressed during the study (sudden death, pneumonia, and post-PZ withdrawal pump failure). Prazosin is a valuable vasodilator for long-term treatment of otherwise refractory congestive heart failure with the agent given in sufficient individualized dosage.

Aged↗

[Accuracy of clinical findings in patients with disturbed myocardial function in acute myocardial infarction].

The relationship between clinical findings and invasively measured hemodynamic data was investigated in a prospective trial of 70 patients with acute myocardial infarction. In 26 out of 27 consecutive patients without clinical signs of disturbed myocardial function, normal hemodynamic values were also found invasively. In 43 patients, depressed myocardial function was diagnosed on the basis of the clinical findings. These findings were verified in 38 patients (88%) by means of cardiac catheterization; 5 patients (12%) had normal hemodynamic values. In 26 patients with clinical signs of congestive heart failure, an attempt was made to identify non-invasively those with a low output (cardiac index less than 2/min/m2). Only 3 of the 6 patients with a low output could be identified by clinical examination alone. In one patient a low output was clinically diagnosed despite normal cardiac function measured invasively. In 16 patients, 48 subsequent clinical examinations were performed during treatment of congestive heart failure to identify either persistent elevated left ventricular filling pressure or low output; 15 (31%) were found to be incorrect when compared with the cardiac catheterization data. Patients with acute myocardial infarction and normal ventricular function can be identified with high accuracy by means of clinical examination alone. The clinical diagnosis of congestive heart failure was incorrect in 12% of the patients. A low output state in acute myocardial infarction is often overlooked in clinical examination alone. Of the clinical examinations on patients during therapy, 30% were incorrect. Invasive hemodynamic monitoring in acute myocardial infarction therefore appears to be unnecessary in patients with normal clinical findings, but in those with clinically diagnosed congestive heart failure it is mandatory for precise indication and evaluation of therapy.

Cardiac Catheterization↗

[Basic concepts in hemodynamic monitoring in intensive care].

The interpretation of hemodynamic measurements in intensive care must be based on a knowledge of how blood flow, blood pressure and blood volume are regulated. The adrenergic nervous system plays a pivotal role in control of these circulatory functions. Blood pressure and blood flow are regulated via the variation of heart rate, cardiac contractility, peripheral vascular resistance, and redistribution and retention of volume. The assessment of quantitative measurements and of formal abnormalities of detected pressure curves, in conjunction with considerations on compensatory mechanisms, render possible a logical approach to therapy.

Critical Care↗

Plasma catecholamines and cardiac, renal and peripheral vascular adrenoceptor-mediated responses in different age groups of normal and hypertensive subjects.

The role of the sympathetic nervous system in cardiac, renal and peripheral vascular adrenoceptor-mediated responses was investigated in patients with essential hypertension and age-matched normotensive subjects. Regardless of age plasma adrenaline was significantly higher in hypertensive when compared with normotensive subjects. This suggests a sympatho-adrenal factor in essential hypertension. Plasma noradrenaline tended to increase with age but its similarity between normotensive and hypertensive subjects points to similar postganglionic neural activity and/or similar overflow of noradrenaline into the circulation. On the other hand, beta-adrenoceptor-mediated tachycardia in response to exercise and intravenous isoproterenol as well as the forearm vasodilator response to intraarterial isoproterenol decreased in normal subjects with older age. In hypertensives this age-dependent beta-receptor-related effect tends to be enhanced as judged from the greater reduction of cardiac isoproterenol sensitivity and the blunted renin response to exercise stimulation. The dilator response to alpha-adrenoceptor blockade with phentolamine was not different in both groups. Therefore a qualitative rather than quantitative derangement of sympathetic control of vascular resistance - in which beta-dilator effects are reduced and alpha-constrictor mechanisms prevail - may contribute to the maintenance of established hypertension.

Adult↗

[Hemodynamic consequences of the furosemide treatment of cardiac insufficiency in recent myocardial infarct].

Furosemide was administered intravenously to 11 patients with cardiac failure after acute myocardial infarction. After an initial loading dose furosemide was given four-hourly if the pulmonary capillary wedge pressure (PCW) was not normalized, i.e. less than or equal to 15 mm Hg. The comparison of the hemodynamic results with the results of a previous study with nitrates was as follows: like the nitrates furosemide lowered the PCW early, i.e. within 15 minutes from 22 +/- 3 to 18 +/- 5 mm Hg, but the therapeutic objective (PCW less than or equal to 15 mm Hg) was reached later than with nitrates. During the 24-hour observation period PCW and total peripheral resistance decreased steadily. The decrease of cardiac index to critical low values in some patients after a mean of 7.5 hours of therapy, and of the mean arterial pressure from 100 +/- 13 to 91 +/- 14 mm Hg, may limit the use of furosemide alone in these patients. During nitrate therapy PCW started to rise again after 12 hours in some patients, necessitating higher doses of nitrates with a corresponding decrease of diuresis. A combination of both forms of therapy may be of value and needs further investigation.

Aged↗

[High spontaneous variability of ventricular arrhythmias limits the evidence gained by long-term ECG studies].

The spontaneous variability of ventricular arrhythmias was investigated in 8 patients with chronic coronary heart disease. In each patient 6 eight-hour long-term ambulatory ECG recordings were made. During the first three periods patients were without medication and during the following three periods they received a placebo b.i.d. Hour to hour variability was high in all patients. When compared with the first hour of an eight-hour period the number of ventricular premature beats (VPB) per hour in four patients declined by more than 90%, in two patients by more than 70% and in only two by less than 50%. On the other hand, increments of several hundred percent were often observed. Day to day variability of VPBs was also high. When compared with the first documented eight-hour period VPBs either decreased or increased substantially (-84% to +940%). A spontaneous reduction of VPB's for several hours may simulate an antiarrhythmic drug effect. For the group as a whole placebo had a significant effect on the number of VPBs (p less than 0.001). Beside variations of quantity, the complexity of ventricular arrhythmias (Lown classification) spontaneously changed several classes in one patient. Therefore, high spontaneous variability renders it very difficult to estimate the behaviour of ventricular arrhythmias in the individual patient with the Holter-ECG.

Arrhythmias, Cardiac↗

[Peroral nitrate therapy in severe cardiac insufficiency following acute myocardial infarct].

Ten patients with severe congestive heart failure after acute myocardial infarction were treated with 40 mg isosorbiddinitrate-retard every 4 hours and additional sublingual nitroglycerine. There was a prompt improvement of hemodynamic parameters which was maintained for 24 hours: pulmonary capillary wedge pressure (PCW) decreased within 10 min from 26 +/- 5 (X +/- SEM) to 17 +/- 2 mm Hg (p less than 0.01) and mean arterial pressure from 109 +/- 7 to 98 +/- 6 mm Hg. The heart rate remained constant, and the cardiac index improved from 2.3 +/- 0.2 to 2.5 +/- 0.21/min/m2. The fall in blood pressure was dependent on the pretreatment pressure: it was significantly greater in patients with elevated blood pressure and only slight in those with a low pretreatment blood pressure. In the presented series of patients neither adverse effects or symptoms nor a critical reduction of blood pressure were observed. Combined oral treatment with isosorbiddinitrate and nitroglycerine can therefore be carried out without invasive blood pressure monitoring.

Administration, Oral↗