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Biomedical subjects

O Bertel

Publications and source records attributed to O Bertel.

137 records · Page 8Linked to original sources
PubMed1977

[Stress hemodynamics in fresh myocardial infarct].

Hemodynamic measurements before and during graded leg-up tilt were performed in 20 patients on the 1st and 3rd day following myocardial infarction. In those with an elevated pulmonary capillary pressure (greater than 11 mm Hg), independent of the cardiac index, the tilt-test (i.e. an additional increase in preload) unmasked heart failure. When applied to test drug responses, furosemide (n = 7) reduced the tilt-stimulated cardiac index with an attendant fall in pulmonary capillary pressure; nitroglycerine (n = 7) did not change cardiac index but reduced the pulmonary capillary pressure.

Cardiac Output↗
PubMedDate not supplied

Decreased Beta-adrenoreceptor responsiveness as related to age, blood pressure, and plasma catecholamines in patients with essential hypertension.

The role of the sympathetic nervous system as it relates to adrenoreceptor-mediated hemodynamic responses was investigated in patients with essential hypertension and in normal subjects of similar age. An age-related increase in plasma norepinephrine (PNE) concentrations observed in 36 recumbent normal subjects (r = 0.623, p less than 0.001) was not found in 56 patients; the latter included some young patients with high values. Sympathetic overactivity in patients (n = 24) as compared with normotensive subjects (n = 20) was suggested by a greater increase in PNE upon standing (242 +/- 34 vs 155 +/- 25 pg/ml (SEM), p less than 0.05) and persistently higher plasma epinephrine (PE) concentrations at rest and during equieffective exercise (p less than 0.05). In patients, PNE was directly related to systolic (r = 0.57, p less than 0.01) and diastolic (r = 0.53, p less than 0.01) blood pressure. Older age was associated with diminished exercise tachycardia and increased blood pressure responses to exercise, which were both more pronounced in hypertensive patients. This higher pressure/lower heart rate pattern was paralleled by an age-related decrease in isoproterenol sensitivity in normal subjects (0.97 +/- 0.15 in six below age 34 years, 1.31 +/- 0.30 in eight between 35--49 years, and 1.82 +/- 0.12 microgra/m2 in six above 50 years), which was also more pronounced (p less than 0.05) in hypertensive patients (1.20 +/- 1.18 in seven below age 34 years, 2.42 +/- 0.30 in nine between 35--49 years, and 6.73 +/- 2.44 micrograms/m2 in eight above 50 years). Thus, an increase in the patients' blood pressure and age is associated with a progressive reduction in beta-adrenoreceptor sensitivity and/or reactivity. Defective beta-adrenoreceptor-mediated responses may result in unopposed alpha-adrenoreceptor-mediated vasoconstriction and thereby contribute to the development of hypertension.

Adult↗
PubMedDate not supplied

Factors influencing the hypotensive effects of calcium antagonists.

The antihypertensive efficacy of monotherapy with the calcium antagonists nifedipine (n = 60) and verapamil (n = 43) was investigated in patients with essential hypertension. Relationships between age, pretreatment blood pressure, pretreatment plasma renin activity, and hypotensive response were examined. Intraindividual differences in the responses to both drugs were also studied (n = 16). Treatment with verapamil had to be discontinued because of constipation in one patient; treatment with nifedipine was discontinued because of headache in 11 and ankle edema in one. The antihypertensive efficacy of nifedipine and verapamil was comparable and was positively related to pretreatment mean blood pressure (p less than 0.001) and inversely to pretreatment plasma renin activity (p less than 0.05). With verapamil, the fall in blood pressure correlated positively with the patient's age (p less than 0.001). Thus, calcium antagonists can be used as first-line drugs, especially in older and low renin patients. The relationship between the antihypertensive response and pretreatment blood pressure suggests that there may be a calcium influx-dependent vasoconstrictor mechanism in essential hypertension which may be more pronounced in patients with low plasma renin.

Administration, Oral↗