title: Electrocardiographic and scintigraphic evaluation of patients with subclinical hyperthyroidism during workout.
abstract: Subclinical hyperthyroidism (sHT) was found to be associated with elevated heart rate, blood pressure and increased risk of extrasystoles. However, the full clinical relevance of morphological and functional implications of sHT on the cardiovascular system is still a matter of debate. The aim of the study was to prospectively assess the influence of endogenous sHT on exercise capacity and cardiac function during workout with the use of exercise electrocardiography (ExECG) and perfusion scintigraphy. The studied group consisted of 44 consecutively recruited patients diagnosed with sHT. In all patients, ExECG, followed by post-exercise myocardial perfusion imaging, was performed. Both ExECG and scintigraphy were performed twice-in the state of sHT and after euthyroidism was restored. An average time period of exercise test was significantly longer in the state of euthyroidism than in sHT. An average oxygen consumption during exercise test was also higher after euthyroidism was achieved when compared to sHT. The end-diastolic and end-systolic volume indexes, stroke volume index and cardiac index were significantly larger in patients with sHT if compared values achieved after euthyroidism restoration. Stroke volume index was negatively correlated with TSH, and positively with free thyroid hormones values in the state of sHT, before euthyroidism was achieved. Cardiac index was positively correlated with free thyroid hormones levels. The obtained results indicate worse physical capacity in subjects with sHT and improvement of several parameters assessed during ExECG and perfusion scintiscan after therapy. Observed changes might reflect the mechanism of the deleterious effect exerted by sHT on the heart.
authors: Department of Endocrinology and Isotope Therapy, Military Institute of Medicine, Szaserów St 128, 04-141, Warsaw, Poland. gkaminski@wim.mil.pl.
authors: Grzegorz
authors: G
authors: Kaminski
authors: Department of Nuclear Medicine, Military Institute of Medicine, Szaserów St 128, 04-141, Warsaw, Poland.
authors: Mirosław
authors: M
authors: Dziuk
authors: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, 49 Przybyszewskiego St, 60-355, Poznan, Poland.
authors: Ewelina
authors: E
authors: Szczepanek-Parulska
authors: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, 49 Przybyszewskiego St, 60-355, Poznan, Poland.
authors: Ariadna
authors: A
authors: Zybek-Kocik
authors: Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, 49 Przybyszewskiego St, 60-355, Poznan, Poland.
authors: Marek
authors: M
authors: Ruchala
mesh_terms: D000328:Adult; D000368:Aged; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D011877:Radionuclide Imaging; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology*; D013963:Thyroid Hormones / Q000097:blood; D055815:Young Adult
chemical_list: D013963:Thyroid Hormones
keywords: Exercise electrocardiogram; Perfusion scintigraphy; Subclinical hyperthyroidism; Workout