Altered cardiovascular vagal responses in nonelderly female patients with subclinical hyperthyroidism and no apparent cardiovascular disease
| Autor: | Alexandru Buescu, Mario Vaisman, Cláudia Medina Coeli, Roberto Coury Pedrosa, Renata Boschi Portella |
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| Rok vydání: | 2007 |
| Předmět: |
Adult
medicine.medical_specialty Cross-sectional study Endocrinology Diabetes and Metabolism Thyrotropin Exercise intolerance Autonomic Nervous System Cardiovascular System Hyperthyroidism Tilt table test Electrocardiography Endocrinology Heart Rate Tilt-Table Test Internal medicine medicine Heart rate variability Humans Vagal tone Subclinical infection medicine.diagnostic_test business.industry Vagus Nerve Middle Aged Thyroxine Cross-Sectional Studies Circulatory system Female medicine.symptom business |
| Zdroj: | Clinical endocrinology. 67(2) |
| ISSN: | 0300-0664 |
| Popis: | Summary Objective Subclinical hyperthyroidism (SH) has been associated with exercise intolerance, changes in cardiac morphology, atrial arrhythmias and sympathovagal imbalance. The aim of this study was to evaluate the vagal reserve and modulation by a sympathetic stimulus in nonelderly patients with SH without cardiovascular problems. Design We carried out a cross-sectional study, comparing data of the heart rate variability (HRV) of SH patients and healthy controls at rest and after vagal and sympathetic stimulation. Patients We studied 16 female patients with at least 6 months of SH and 16 healthy female controls with the same median age (40 vs. 34·5 years). Measurements We used the tilt test, with electrocardiographic record at rest, during the respiratory sinus arrhythmia (RSA) manoeuvre and after tilting, in order to analyse HRV in the frequency domain (%high frequency (HF) and low/high frequency ratio (LF/HF) using Biopotentials Captation System software. Results The median TSH level was 0·03 mU/l in patients and 1·37 mUI/l in controls. The median free T4 was 1·37 ng/dl in patients and 1·20 ng/dl in controls. Patients demonstrated a significantly smaller difference between %HF during the RSA and %HF at rest than controls (median –7·5 vs. 36·6, P |
| Databáze: | OpenAIRE |
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