Assessment of left ventricular diastolic function by radionuclide ventriculography at rest and exercise in subclinical hypothyroidism, and its response to L-thyroxine therapy
| Autor: | Gabriela Brenta, Luis Alberto Mutti, Alberto Perrone, Osvaldo Fretes, Marta Schnitman, María Luisa Matute |
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| Rok vydání: | 2003 |
| Předmět: |
Cardiac function curve
Male endocrine system medicine.medical_specialty endocrine system diseases Rest Levothyroxine Diastole Radionuclide ventriculography Physical exercise Blood Pressure Electrocardiography Ventricular Dysfunction Left Hypothyroidism Heart Rate Internal medicine medicine Humans Euthyroid Exercise Radionuclide Ventriculography Subclinical infection medicine.diagnostic_test business.industry Middle Aged Thyroxine Cholesterol Cardiology Physical Endurance Female Cardiology and Cardiovascular Medicine business medicine.drug |
| Zdroj: | The American journal of cardiology. 91(11) |
| ISSN: | 0002-9149 |
| Popis: | Hypothyroidism is associated with intrinsic myocardial changes reflected by alterations in contractility and relaxation. Diastolic function, however, rather than systolic cardiac function, seems to be mostly impaired by thyroid hormone deprivation. Our aim was to evaluate diastolic function at rest and during maximal exercise by means of radionuclide ventriculography in subclinical hypothyroidism before and after restoration of euthyroidism. Ten subclinical hypothyroid patients (50 +/- 8.7 years) (thyroid-stimulating hormone 11 +/- 4.2 microUI/ml) without cardiac disease were studied before and 6 months after levothyroxine (L-T(4)) replacement (thyroid-stimulating hormone 1.9 +/- 1.1 microUI/ml). We compared the basal and post-therapy cardiac parameters with a control group of 14 euthyroid patients (52.5 +/- 10 years) (thyroid-stimulating hormone 2.5 +/- 1.2 microUI/ml). Multigated equilibrium radionuclide ventriculography was performed to assess systolic and diastolic ventricular function. Student's t and paired Student's t tests were applied for statistical analysis. We found a significant difference between the time to peak filling rate (TPFR) at rest before (0.241 +/- 0.002 ms) and after (0.190 +/- 0.012 ms) treatment with L-T(4). A significant difference that disappeared after restoration of euthyroidism was also observed between the basal TPFR values of the subclinical hypothyroid patients and the control group (0.189 +/- 0.01 ms). The same pattern was observed at maximal exercise. Thus, TPFR, a parameter of left ventricular (LV) diastolic function measured by radionuclide ventriculography, is impaired in subclinical hypothyroid patients both at rest and during exercise and returns to normal values after L-T(4) therapy. |
| Databáze: | OpenAIRE |
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