CARDIAC STRAIN IN WOMEN WITH A DOCUMENTED HISTORY OF OVERT OR SUBCLINICAL HYPOTHYROIDISM: AN EXPLORATORY SPECKLE-TRACKING ECHOCARDIOGRAPHY STUDY.

AIM: To compare conventional and speckle-tracking echocardiographic parameters, with a prespecified focus on left atrial (LA) contractile strain, between women with a documented history of hypothyroidism and euthyroid controls. MATERIAL AND METHODS: This retrospective case-control analysis included 86 women: 36 with a previously documented diagnosis of overt or subclinical hypothyroidism and 50 controls documented as euthyroid. The hypothyroid cohort was clinically heterogeneous and included treated and untreated participants; 31 (86.1%) were receiving L-thyroxine. Conventional transthoracic echocardiography and two-dimensional speckle-tracking analysis were evaluated. LA contractile strain was the prespecified primary outcome; other echocardiographic comparisons were exploratory. Multivariable linear regression adjusted for age, body mass index, diastolic blood pressure, and heart rate. RESULTS: The hypothyroid group was younger than controls. Left ventricular ejection fraction was preserved in both groups. Hypothyroid participants had lower LV volumes, LA volume index, pulmonary artery systolic pressure, and right-ventricular (RV) S'. RV free-wall strain and the magnitude of LA contractile strain were lower, whereas LV global longitudinal strain, RV global longitudinal strain, LA reservoir strain, and LA conduit strain did not differ. In the subset with available free thyroxine data (n=21), FT4 correlated with signed LA contractile strain (ρ=0.524, p=0.015). After adjustment, hypothyroidism was not independently associated with LA contractile strain (B=2.634, 95% CI -0.081 to 5.349; p=0.057); heart rate remained independently associated (B=-0.145, 95% CI -0.263 to -0.027; p=0.017). CONCLUSIONS: In this heterogeneous cohort of women with treated or untreated overt or subclinical hypothyroidism, unadjusted differences in RV free-wall and LA contractile strain were observed. The adjusted analysis did not establish an independent association between hypothyroidism and LA contractile strain. These exploratory findings require confirmation in prospectively recruited, age-matched cohorts with standardized biochemical phenotyping.