Comparison of myocardial deformation indices during rest and after activity in untreated hyperthyroid patients with normal population

Abstract

Background: Thyroid hormones play an essential role on the cardiovascular system. Also, thyroid diseases have a prominent adverse effect on myocardial and vascular functions. Therefore, the aim of this study was to compare myocardial deformation indices during resting and after activity between the untreated hyperthyroid patients and normal population.

Methods: We included 26 untreated participants who were newly diagnosed with hyperthyroidism and 26 healthy participants matched in terms of age and sex. The left ventricular end-diastolic volume index (LVEDVI), Heart Rate (HR), Cardiac Output (CO), systolic and diastolic blood pressures, Global Longitudinal Strain (GLS), Global Circumferential Strain (GCS), Rate-Pressure Product (RPP), systolic and diastolic strains rates were measured in rest and peak of exercise in stress echocardiography.

Results: Age and sex distributions were similar among the groups. Also, mean serum TSH was 0.08 ± 0.08 ng/dL in the case group. The participants with the untreated hyperthyroidism had lower Ejection Fraction change (ΔEF), GLS, peak stress systolic and diastolic strains rates compared to the control group. Also, there was a positive association between TSH levels and basal HR, RPP, CO, as well as a negative correlation with basal and maximum GLS, ΔHR, ΔEF, and ΔCO. Also, a duration of symptoms had a linear association with rest HR, CO, and LVEDVI, as well as a negative correlation with rest and maximal GLS, ΔHR, and ΔGLS.

Conclusion: Myocardial deformation assessed by 2DE imaging are significantly impaired in the hyperthyroid patients. In this regard, further studies with a larger sample size are required to confirm the results of this study.

Keywords: Hyperthyroidism; global circumferential strain; global longitudinal strain; myocardial deformation; tissue Doppler imaging.

Figure 1

Left ventricular strain rate in a hyperthyroid patient at peak of stress test (heart rate about 160 bpm). Systolic strain rate is about 0.27 s^-1 that is significantly lower than control subjects.

Figure 2

Left ventricular Global Longitudinal Strain (GLS) in a hyperthyroid patient at peak of stress test (-18.2%) that showed a subtle increase in GLS from resting GLS (not showed here) compared to control subjects.