Power spectral analysis of heart rate in hypothyroidism
| Autor: | Giacomo Zoppini, Roberto Castello, M. L. Gemma, M. E. De Gregori, Paolo Moghetti, Vittorio Cacciatori, Michele Muggeo, Karl Thomaseth, F. Bellavere |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2000 |
| Předmět: |
medicine.medical_specialty
Sympathetic nervous system Sympathetic Nervous System AUTONOMIC NEUROPATHY Valsalva Maneuver Endocrinology Diabetes and Metabolism medicine.medical_treatment Levothyroxine Diaphragmatic breathing SYMPATHETIC-NERVE ACTIVITY PLASMA NORADRENALINE THYROID-HORMONE SYMPATHOVAGAL BALANCE Immunoenzyme Techniques Parasympathetic nervous system Electrocardiography Endocrinology Hypothyroidism Heart Rate Parasympathetic Nervous System Internal medicine Heart rate medicine Valsalva maneuver Heart rate variability Humans medicine.diagnostic_test business.industry General Medicine Middle Aged Thyroxine medicine.anatomical_structure Female business medicine.drug |
| Zdroj: | Scopus-Elsevier |
| Popis: | OBJECTIVE: The aim of the present study was to evaluate the impact of hypothyroidism on the autonomic regulation of the cardiovascular system by analysing separately sympathetic and parasympathetic influences on the heart. DESIGN: In seven newly diagnosed untreated hypothyroid patients we analysed power spectral density of heart rate cyclic variations at rest, while lying, and while standing. The same protocol was repeated after the induction of stable euthyroidism by levothyroxine (L-T(4)) treatment. The results were also compared with those obtained from seven age-, sex- and body mass index-matched control subjects. METHODS: Heart rate variability was evaluated by autoregressive power spectral analysis (PSA). This method allows reliable quantification of low frequency (LF) and high frequency (HF) components of the heart rate power spectral density. These are considered to be under mainly sympathetic and purely parasympathetic control respectively. In addition, heart rate variations during deep breathing, lying to standing, and Valsalva's manoeuvre were assessed. RESULTS: PSA showed a sharp reduction in the HF (parasympathetic) component in hypothyroid subjects compared with controls (lying, 29.4+/-5.4 vs 47.7+/-6.3 normalized units (NU) (means +/- s.e.m.), P |
| Databáze: | OpenAIRE |
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