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).


METHODS
Prospective, single-blinded, placebo-controlled randomized trial of 6 months duration with two parallel groups.


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.


CONCLUSIONS
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.
Abdulrahman
Randa M
RM
Department of Endocrinology and Metabolism, C4-R, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.
Delgado
Victoria
V
Ng
Arnold C T
AC
Ewe
See Hooi
SH
Bertini
Matteo
M
Holman
Eduard R
ER
Hovens
Guido C
GC
Pereira
Alberto M
AM
Romijn
Johannes A
JA
Bax
Jeroen J
JJ
Smit
Johannes W
JW
D000328:Adult; D001794:Blood Pressure; D015331:Cohort Studies; D004452:Echocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*