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  • myocardial infarction  (2)
  • Non-invasive blood pressure  (1)
  • 1
    ISSN: 1432-1041
    Keywords: beta-blocking drugs ; coronary artery disease ; myocardial infarction ; haemodynamic response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Theoretically the increased sympathoadrenal activity following acute myocardial infarction might augment the haemodynamic impact of beta-adrenoceptor blockade. To evaluate this question 32 haemodynamic studies were performed to compare the effects of equivalent beta-blocking doses of propranolol (8 mg i.v.) and pindolol (0.8 mg i.v.) in patients with a recent acute myocardial infarction (A.M.I.) or stable coronary artery disease (and a presumptive low sympathetic state). In stable coronary artery disease there were clear differences between the haemodynamic impact of propranolol and pindolol. Propranolol decreased both heart rate (ΔHR −7 beat/min) and cardiac index (ΔCI −0.4l/min/m2), with an increased pulmonary artery occluded pressure (ΔPAOP +4 mmHg) and systemic vascular resistance index (ΔSVRI +358 dyn · s · cm−5 m2). However an equivalent beta-blocking dose of pindolol increased PAOP (ΔPAOP +3 mmHg) leaving other variables unchanged. These differential actions of propranolol and pindolol have previously been ascribed to the intrinsic synpathomimetic activity (I.S.A.) of pindolol maintaining cardiac pumping function in a low sympathetic state. In contrast following myocardial infarction, both drugs reduced cardiac index to a significantly greater extent compared with stable coronary artery disease (ΔCI propranolol −0.8l/min/m2; pindolol −0.4l/min/m2;p〈0.05); propranolol also reduced the systemic arterial blood pressure (Δsystolic −10 mmHg; Δmean −5 mmHg;p〈0.05). The haemodynamic relevance of the I.S.A. of pindolol appeared attenuated following A.M.I. These data are compatible with experimental evidence of sympathetic nervous activation following coronary occlusion; the resulting hyperadrenergic state appears to condition an augmented haemodynamic response to beta-blocking drugs irrespective of their ancillary pharmacological properties. The implications of these findings for clinical therapy warrant further examination.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1041
    Keywords: beta-receptor blocking drugs ; myocardial infarction ; haemodynamic effects ; propranolol ; pindolol ; intrinsic sympathomimetic activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The relevance of the intrinsic sympathomimetic activity (ISA) of beta-blocking compounds to the clinical therapeutics of acute myocardial infarction was evaluated in 20 patients with an uncomplicated acute myocardial infarction by comparing the haemodynamic effects of equivalent beta-blocking doses of propranolol (non-cardioselective; no ISA) and pindolol (non-cardioselective; 50% ISA). Consecutive eligible male patients admitted to a Coronary Care Unit were randomised following a 1 h control period to two separate studies. In Study 1 the short-term dose-response effects of propranolol (1–8 mg) or pindolol (0.1–0.8 mg) were assessed. In Study 2 comparison of the effects of single i.v. propranolol (8 mg) and pindolol (0.8 mg) doses was undertaken over 6 h. Haemodynamic variables and thermodilution cardiac output were subsequently recorded to compare the effects of each drug on the circulation. The plasma concentrations of propranolol and pindolol were in the recognised therapeutic range. Both drugs were clinically well-tolerated, the changes induced in haemodynamic variables following each drug demonstrated effective beta-blockade. Within the limits of the experimental protocol, these data did not suggest definite haemodynamic advantage for ISA of pindolol in acute myocardial infarction. These findings are perhaps due to sympathetic activation in acute myocardial infarction attenuating the haemodynamic impact of ISA.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1619-1560
    Keywords: Finapres ; Non-invasive blood pressure ; Exercise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The accuracy and precision of the Finapres in recording rest and exercise blood pressure compared with the intra-arterial (aortic and brachial) and random-zero sphygmomanometer methods was assessed in 84 ischaemic patients in three different studies. Firstly, comparison at rest with the aortic intraarterial pressure in 50 ischaemic patients demonstrated that the Finapres systolic (136.5 ± 21.1 vs. 129.3 ± 19.0 mmHg;p 〈 0.001) and mean (92.4 ± 13.4 vs. 90.7 ± 11.4 mmHg;p 〈 0.001) arterial pressures were higher and diastolic pressures lower (70.4 ± 11.5 vs. 71.5 ± 9.8 mmHg;p 〈 0.001). The reproducibility of the Finapres and invasive method was similar for systolic (4.6% vs. 4.0%), diastolic (2.8% vs. 2.7%) and mean (3.3% vs. 3.0%) blood pressures. Second, in seven subjects studied twice at rest and during 4 min supine bicycle exercise, the exercise increase in blood pressure was greater on the Finapres compared with the brachial intra-arterial pressure (systolic +10.2 ± 6.3 vs. +3.6 ± 9.8 mmHg; diastolic +9.6 ± 11.1 vs. +0.2 ± 2.1 mmHg;p = 0.02 for each); however, at steady-state the peak/trough differences in pressure between the methods were similar. Thirdly, compared under rest conditions, to random zero sphygmomanometer (RZO), the Finapres systolic pressure was higher (6.8 ± 3.5 mmHg) and diastolic pressure lower (−6.0 ± 1.9 mmHg). During upright bicycle exercise, the difference between the Finapres and RZO in systolic blood pressure increased at each level of exercise (+14.3 ± 4.2, +17.9 ± 4.0 and +22.2 ± 4.1 mmHg respectively at each exercise stage:p 〈 0.01). For RZO, diastolic blood pressure fell as exercise workload increased whereas Finapres diastolic blood pressure increased on exercise (3.1 ± 2.6, 7.0 ± 2.1 and 8.1 ± 2.0 mmHg respectively:p 〈 0.01). Thus there were systematic differences between the values recorded by the Finapres and proximal blood pressure methods and limited agreement in the rest to exercise increments related to light exercise. Calibration of the Finapres values in terms of the other methods is limited by the variable relationship to these related changes in arterial distensibility.
    Type of Medium: Electronic Resource
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