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Cardiac function at rest in hypothyroidism evaluated by equilibrium radionuclide angiography
Author(s) -
Tielens Emile T.,
Pillay Marrmuthoo,
Storm Corstiaan,
Berghout Arie
Publication year - 1999
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1999.00662.x
Subject(s) - radionuclide angiography , medicine , cardiac function curve , cardiology , diastolic function , diastole , cardiac output , doppler echocardiography , ejection fraction , hemodynamics , heart failure , blood pressure
OBJECTIVE Previous studies have suggested that hypothyroidism affects both systolic and diastolic cardiac function. We have applied equilibrium radionuclide angiography to the study of heart function at rest in hypothyroidism. DESIGN A prospective study, evaluating cardiac function at rest in primary hypothyroidism. METHODS Cardiac function was studied by means of equilibrium radionuclide angiography. Screening echo‐Doppler examinations were performed on each patient. PATIENTS Twenty‐six consecutive untreated hypothyroid patients without clinical or echocardiographic cardiac disease and 20 healthy matched controls. RESULTS Between patients and controls, the time to peak emptying rate (161 ± 6 msec vs . 144 ± 6 msec, P < 0.05) and the time to peak filling rate (188 ± 6 msec vs . 170 ± 5 msec, P < 0.05), were the only discriminatory parameters. In hypothyroid patients, a trend towards a decrease in diastolic cardiac function, expressed as peak filling rate, was observed: 2.6 ± 0.1 End Diastolic Volume (EDV)/s vs . 3.0 ± 0.1 EDV/s, P = 0.06. Within the hypothyroid patient group, the time to peak emptying rate was more prolonged in patients with lower free thyroxine levels ( R = − 0.60, F = 13.5, P < 0.001). Peak filling rate was decreased in patients with lower free thyroxine levels ( R = 0.51, F = 8.4, P < 0.01) whereas the time to peak filling rate was more prolonged ( R = − 0.62, F = 15, P < 0.001). CONCLUSION In a large group of consecutive patients presenting with primary hypothyroidism, even in the absence of clinical cardiac disease and echocardiographic abnormalities, clear changes in myocardial performance at rest were observed. The most obvious effect of thyroid hormone deficiency on the heart was a lengthening of both systolic and early diastolic time characteristics. Diastolic rather than systolic cardiac function was influenced by hypothyroidism.