During 12 weeks' administration, 10 microg vaginal tablets resulted in at least 50% lower mean estradiol concentrations than with the 25 microg dose within 24 h after dosing. Administering the 25 microg dose, mean E2 levels during the first 2 weeks exceeded the published reference range for postmenopausal women using the GCMS method, while, with the 10 microg dose, mean E2 levels remained in that range from the beginning, indicating minimized estradiol absorption.
The new HES specification demonstrated favourable pharmacokinetic properties compared with other HES specifications of medium or high molecular weight. No clinically relevant plasma accumulation and related undesired effects on haemostasis are expected to occur under multiple-dose conditions.
The effect of acute thyroid hormone deficiency on left ventricular diastolic filling was studied by radionuclide ventriculography with simultaneous right heart catheterization in nine athyreotic patients without cardiovascular disease. The patients were studied when they were hypothyroid and when they were euthyroid on replacement therapy. Peak filling rate and the time to peak filling were used to characterize diastolic function. The time to peak filling was defined as the interval from end-systole on the radionuclide time-volume curve to the time of occurrence of peak filling. The peak filling rate was determined in absolute terms from the normalized radionuclide peak filling rate and from the end-diastolic volume, which was derived from the radionuclide ejection fraction and from the thermodilution stroke volume. In all patients, the values for peak filling rate were lower in the hypothyroid than in the euthyroid state (287 +/- 91 mL/s vs. 400 +/- 118 mL/s, delta = 41 +/- 13%, p less than 0.01). Peak filling always occurred during the first half of the diastolic interval. The time to peak filling was not significantly affected by the thyroid state (170 +/- 10 ms vs. 159 +/- 21 ms, delta = 7 +/- 10%). Left ventricular filling pressure as reflected by the pulmonary capillary wedge pressure and end-systolic volume were similar in both thyroid states (6 +/- 2 mmHg vs. 8 +/- 2 mmHg (1 mmHg = 133.32 Pa) and 32 +/- 11 mL vs. 32 +/- 7 mL, respectively). The data suggest that the rate of active diastolic relaxation is decreased in short-duration hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)
SUMMARY The effect of hypothyroidism on left ventricular function at rest and during exercise was studied in nine patients without demonstrable cardiovascular disease who had had total thyroidectomy and ablative radioiodine treatment for thyroid cancer. Radionuclide ventriculography and simultaneous right heart catheterisation were performed while the patients were hypothyroid two weeks after stopping triiodothyronine treatment (to permit routine screening for metastases) and while they were euthyroid on thyroxine replacement treatment. When the patients were hypothyroid, cardiac output, stroke volume, and end diastolic volume at rest were all lower and peripheral resistance was higher than when they were euthyroid. Pulmonary capillary wedge pressure, right atrial pressure, heart rate, left ventricular ejection fraction, and the systolic pressure:volume relation of the left ventricle, which was used as an estimate of the contractile state, were not significantly different when the patients were hypothyroid or euthyroid. During exercise, heart rate, cardiac output, end diastolic volume, and stroke volume were higher when the patients were euthyroid than when they were hypothyroid. Again, pulmonary capillary wedge pressure, ejection fraction, and the systolic pressure:volume relation were similar in both thyroid states.The data suggest that the alterations in cardiac performance seen in short term hypothyroidism are primarily related to changes in loading conditions and exercise heart rate; they do not suggest that acute thyroid hormone deficiency has a major effect on the contractile properties of the myocardium.Thyroid hormone deficiency is known to affect the heart.`13 Although exercise intolerance is a classic feature of hypothyroidism, most studies have focused on the contractile function of the heart at rest' and little attention has been paid to the performance of the left ventricle during exercise.Some radionuclide studies assessed the response of the ejection fraction to stress in hypothyroid patients.7' The ejection fraction is widely accepted as a useful measure of ventricular performance'0 but it has limitations. Because it is the ratio of two physiological variables the size of the left ventricular chamber can change considerably without causing a significant change in ejection fraction. So the Requests for reprints to Dr Siegfried Wieshammer, Cardiology Section, Department of Internal Medicine, University of Ulm, Steinhovelstraf3e 9, D-7900 Ulm, Federal Republic of Germany.Accepted for publication 9 November 1987 haemodynamic consequences of hypothyroidism are only incompletely evaluated by the response of the ejection fraction to stress, and for a more comprehensive assessment left ventricular volumes and pressures must be measured. More importantly, the ejection fraction is dependent not only on the intrinsic contractile state of the heart but also on the preload and afterload." Changes in loading conditions seem to be especially important when thyroid function is abnormal'2 and, therefore, it is u...
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