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Effects of short‐term levothyroxine therapy on myocardial injuries in patients with severe overt hypothyroidism: Evidence from a cardiac MRI Study
Author(s) -
Gao Xia,
Chen Zhe,
Liu Min,
Jia YuMei,
Yang Ning,
Yao Zhi,
Feng XiaoMeng,
Xu Yuan,
Wang Guang
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25628
Subject(s) - levothyroxine , medicine , ejection fraction , cardiology , cardiac function curve , stroke volume , magnetic resonance imaging , fractional shortening , heart failure , thyroid , radiology
Purpose To investigate using magnetic resonance imaging (MRI) myocardial injuries and cardiac function in patients with newly diagnosed severe primary overt hypothyroidism (HT) before and after achieving euthyroidism by short‐term levothyroxine treatment. Levothyroxine treatment improves cardiovascular performance and ventricular remodeling in patients with HT, but diffuse myocardial injuries induced by HT are difficult to detect clinically. Materials and Methods Myocardial longitudinal relaxation time ( T 1 ) mapping using the modified Look–Locker inversion‐recovery (MOLLI) sequences at 3.0T was performed before and after euthyroidism was achieved by levothyroxine treatment in 24 patients with Hashimoto's thyroiditis, and compared to 17 healthy controls. Subjects underwent measurements of T 1 values and left ventricular stroke volume (SV), ejection fraction (EF), cardiac index (CI), and peak filling rate (PFR). Cardiac data were expressed as an index, as per body surface area, except for heart rate and EF. Results Patients with untreated HT exhibited significantly longer native myocardial T 1 values (all P < 0.05) accompanied by reduced SV (30.7 ± 5.6 vs. 34.9 ± 6.8 mL/m 2 , P < 0.05), CI (2.1 ± 0.4 vs. 2.4 ± 0.4 L/min/m 2 , P < 0.05), and PFR (3.5 ± 0.9 vs. 4.2 ± 1.1 EDV/s, P < 0.05) compared to healthy controls at baseline. Achieving euthyroidism resulted in a significant decrease in T 1 values and improved SV, CI, and PFR values (all P < 0.05) in the patients with HT. Negative correlations of the T 1 values with free triiodothyronine ( r = –0.55, P < 0.001) and PFR ( r = –0.46, P = 0.0016) were observed. Conclusion We suggest that the negative effect induced by severe overt HT on the cardiovascular system can be significantly improved by restoring euthyroidism with short‐term levothyroxine therapy. Level of Evidence : 1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:897–904