TY - JOUR
T1 - Effect of thyroid hormones on cardiac function, geometry, and oxidative metabolism assessed noninvasively by positron emission tomography and magnetic resonance imaging
AU - Bengel, Frank M.
AU - Nekolla, Stephan G.
AU - Ibrahim, Tareq
AU - Weniger, Carmen
AU - Ziegler, Sibylle I.
AU - Schwaiger, Markus
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2000
Y1 - 2000
N2 - Thyroid hormones influence cardiac performance directly and indirectly via changes in peripheral circulation. Little, however, is known about the effect on myocardial oxidative metabolism and its relation to cardiac function and geometry. Patients with a history of thyroidectomy for thyroid cancer present a unique model to investigate the cardiac effects of hypothyroidism. Ten patients without heart disease were investigated in the hypothyroid state and again 4-6 weeks later under euthyroid conditions. Myocardial oxidative metabolism was measured by positron emission tomography with [11Clacetate and the clearance constant k(mono). Cine magnetic resonance imaging was applied to determine left ventricular geometry. A stroke work index (SWI = stroke volume × systolic blood pressure/ventricular mass) was calculated. Then, to estimate myocardial efficiency, a work metabolic index [WMI = SWI × heart rate/k(mono)] was obtained. Compared to hormone replacement, systemic vascular resistance and left ventricular mass were significantly higher in hypothyroidism. Ejection fraction and SWI were significantly lower. Despite an additional reduction of k(mono), the WMI was significantly lower, too. In summary, cardiac oxygen consumption is reduced in hypothyroidism. This reduction is associated with increased peripheral resistance and reduced contractility. Estimates of cardiac work are more severely suppressed than those of oxidative metabolism, suggesting decreased efficiency. These findings may provide an explanation for development or worsening of heart failure in hypothyroid patients with preexisting heart disease.
AB - Thyroid hormones influence cardiac performance directly and indirectly via changes in peripheral circulation. Little, however, is known about the effect on myocardial oxidative metabolism and its relation to cardiac function and geometry. Patients with a history of thyroidectomy for thyroid cancer present a unique model to investigate the cardiac effects of hypothyroidism. Ten patients without heart disease were investigated in the hypothyroid state and again 4-6 weeks later under euthyroid conditions. Myocardial oxidative metabolism was measured by positron emission tomography with [11Clacetate and the clearance constant k(mono). Cine magnetic resonance imaging was applied to determine left ventricular geometry. A stroke work index (SWI = stroke volume × systolic blood pressure/ventricular mass) was calculated. Then, to estimate myocardial efficiency, a work metabolic index [WMI = SWI × heart rate/k(mono)] was obtained. Compared to hormone replacement, systemic vascular resistance and left ventricular mass were significantly higher in hypothyroidism. Ejection fraction and SWI were significantly lower. Despite an additional reduction of k(mono), the WMI was significantly lower, too. In summary, cardiac oxygen consumption is reduced in hypothyroidism. This reduction is associated with increased peripheral resistance and reduced contractility. Estimates of cardiac work are more severely suppressed than those of oxidative metabolism, suggesting decreased efficiency. These findings may provide an explanation for development or worsening of heart failure in hypothyroid patients with preexisting heart disease.
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U2 - 10.1210/jcem.85.5.6520
DO - 10.1210/jcem.85.5.6520
M3 - Article
C2 - 10843159
AN - SCOPUS:0034458025
SN - 0021-972X
VL - 85
SP - 1822
EP - 1827
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
IS - 5
ER -