Right Ventricular Function Indices at Rest and During Exercise in Hyperthyroid Patients: A Cross-sectional Study

Since hyperthyroidism could be associated with right ventricular dysfunction, this study intended to investigate right ventricular (RV) function using strain echocardiography in hyperthyroid patients both at rest and in maximum-stress conditions.  This cross-sectional study was conducted at Rajaie Cardiovascular Medical and Research Center, Tehran, Iran, from January 2019 to January 2020. All study participants completed a maximum treadmill exercise test, as well as a complete two-dimensional echocardiogram at rest and the peak of stress test. The data were analyzed using SPSS statistical software. The independent samples t test and Mann–Whitney U test were used for numerical, and the Chi square test was used for nominal variables. P<0.05 was considered statistically significant.  The final analysis included 52 participants (26 subjects in each group). In a maximal stress situation, we found that among the RV function indices, RV global longitudinal strain (P=0.0001), systolic strain rate (P=0.0001), diastolic strain rate (P=0.0002), and tricuspid annular plane systolic excursion (P=0.019) were reduced significantly in the hyperthyroid patients compared to the control group. There was also a linear correlation between RV size and thyroid stimulating hormone (TSH) level (P=0.009, r=0.36). Moreover, we found a negative linear correlation between TSH level with maximum stress RV strain and diastolic strain rate (P<0.001). The findings of the present study revealed a significant change in RV function indices among hyperthyroid patients. Therefore, it highlights the necessity of early diagnosis and treatment of hyperthyroidism, as well as RV function evaluation in these patients.