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Direct effect of thyroid hormone on left ventricular myocardial relaxation
1Department of Internal Medicine, Yawatahama City General Hospital, Ehime, Japan.
Insights
Hyperthyroidism impacts left ventricular diastolic function, affecting myocardial relaxation. Echocardiography revealed normalized diastolic indices after treatment, suggesting thyroid hormone levels influence cardiac performance.
Area of Science:
- Cardiology
- Endocrinology
- Medical Imaging
Background:
- Hyperthyroidism can affect cardiac function, particularly left ventricular diastolic properties.
- Understanding these changes is crucial for managing patients with thyroid disorders.
Purpose of the Study:
- To compare left ventricular diastolic indices between hyperthyroid patients and normal controls.
- To investigate the correlation between thyroid hormone levels and diastolic indices.
- To assess the reversibility of diastolic dysfunction after treatment.
Main Methods:
- Echocardiography was used to assess left ventricular diastolic indices in 31 hyperthyroid patients and 49 normal controls.
- Statistical analyses included simple and partial correlation to evaluate relationships between indices and T3 levels.
- A subset of 14 patients was re-examined post-treatment.
Main Results:
- Hyperthyroid patients showed significantly shorter IIa-mitral valve opening time (IIa-MVO) and increased maximum descending rate of the left ventricular posterior wall (maxPWDR), peak E, and peak A compared to controls.
- IIa-MVO, maxPWDR, and peak E demonstrated significant partial correlations with T3 levels.
- Diastolic indices normalized after antithyroid treatment, showing no significant difference from normal controls.
Conclusions:
- Augmented myocardial relaxation in hyperthyroidism correlates with thyroid hormone levels.
- IIa-MVO and maxPWDR are more sensitive indicators of left ventricular myocardial relaxation in hyperthyroidism than peak E and E/A.
- Left ventricular diastolic dysfunction in hyperthyroidism is reversible with treatment.
Abstract:
The left ventricular diastolic indices of the hyperthyroid (HTH) patients without cardiac disease (n = 31) were compared with those of the normal controls (NC) (n = 49) using echocardiography. The HTH group had a significantly shorter IIa-mitral valve opening time (IIa-MVO), and a significantly larger maximum descending rate of the left ventricular posterior wall (maxPWDR), peak E and peak A than the NC group. IIa-MVO, maxPWDR, peak E and E/A showed significant simple correlation with T3 in the HTH group. To elucidate spurious correlation among these indices and T3, partial correlation analysis among these indices and its influencing factors were calculated. IIa-MVO, maxPWDR and peak E showed significant partial correlation coefficients with T3, but peak E had a lesser partial correlation with T3 than with age and left ventricular end-diastolic volume. Fourteen of the hyperthyroid patients were reexamined after antithyroid treatment. Their diastolic indices were found to be normalized compared with pre-treatment values and showed no significant difference with those of NC group. Augmented myocardial relaxation in patients with hyperthyroidism correlated with the thyroid hormone level, and IIa-MVO and maxPWDR were more effective indices of left ventricular myocardial relaxation than peak E and E/A in hyperthyroidism.