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document
Abnormal cardiac contractility in long-term exogenous subclinical hyperthyroid patients as demonstrated by two-dimensional echocardiography speckle tracking imaging . BACKGROUND Subclinical hyperthyroidism is associated with cardiovascular morbidity . Recent advances in echocardiography imaging have allowed sophisticated evaluation of myocardial tissue properties . OBJECTIVE To investigate the myocardial effects of long-term exogenous subclinical hyperthyroidism using two-dimensional speckle tracking echocardiography imaging ( 2D-STE ) . DESIGN Prospective , single-blinded , placebo-controlled randomized trial of 6 months duration with two parallel groups . PATIENTS AND METHODS Totally 25 patients with a history of differentiated thyroid carcinoma on long-term TSH-suppressive levothyroxine ( l-T ( 4 ) ) substitution were randomized to persistent TSH-suppressive l-T ( 4 ) substitution ( low-TSH group ) or restoration of euthyroidism . Additionally 40 euthyroid controls were studied . RESULTS ( PROPOSAL ) : At baseline , the group of patients showed normal left ventricular ( LV ) systolic function but impaired diastolic function as assessed with conventional echocardiographic parameters . Importantly , 2D-STE analysis demonstrated the presence of subclinical LV systolic and diastolic dysfunction with impaired circumferential and longitudinal strain and strain rate at the isovolumic relaxation time . After restoration of euthyroidism , a significant improvement in LV systolic and diastolic function as assessed with 2D-STE strain was observed . CONCLUSION Prolonged subclinical hyperthyroidism leads to systolic and diastolic dysfunction , which is reversible after restoration of euthyroidism . 2D-STE is a more sensitive technique to evaluate subtle changes in LV performance of these patients .
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Intervention_Physical
long-term exogenous subclinical hyperthyroid
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Intervention_Physical
exogenous subclinical hyperthyroidism
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Intervention_Physical
two-dimensional speckle tracking echocardiography imaging ( 2D-STE )
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Intervention_Pharmacological
TSH-suppressive l-T ( 4 ) substitution
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Intervention_Pharmacological
restoration of euthyroidism
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Intervention_Physical
Prolonged subclinical hyperthyroidism
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Outcome_Physical
cardiovascular morbidity .
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Outcome_Physical
myocardial
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Outcome_Physical
normal left ventricular ( LV ) systolic function
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Outcome_Physical
impaired diastolic function
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Outcome_Physical
subclinical LV systolic and diastolic dysfunction
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Outcome_Physical
impaired circumferential and longitudinal strain and strain rate
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Outcome_Physical
improvement in LV systolic and diastolic function
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Outcome_Physical
systolic and diastolic dysfunction
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Participant_Condition
long-term