Endocrine Abstracts

Background: Subclinical hypothyroidism (SCH) is defined as elevated thyroid stimulating hormone (TSH) levels coupled with normal free thyroxine levels. SCH is associated with increased systemic vascular resistance, left ventricular systolic and diastolic dysfunction. Acute myocardial infarction (AMI) represents a leading cause of mortality and morbidity worldwide. AMI can progress to left ventricular systolic dysfunction and heart failure which predicts lower overall survival.

Aims: (i) Evaluate how SCH affects systolic and diastolic function in patients, post-AMI (ii) Assess the prevalence of SCH, post-AMI. (iii) Explore predictors of systolic or diastolic dysfunction post-AMI.

Methods: Patients with AMI (both ST-elevation and non-ST-elevation), were recruited across 6 hospitals in the North-East of England for a 2-year longitudinal prospective cohort study. Thyroid function tests were performed. patient medical characteristics were recorded. Systolic function was evaluated by the left ventricular ejection fraction on echocardiography. Diastolic function parameters included The E wave to A wave ratio (E/A ratio), mitral valve deceleration times (MVDecT) and E/e’ ratio.

Results: Out of 1835 patients there were 321 cases with SCH representing 17.4% of the cohort. SCH was a significant predictor of prolonged MVDecT (P=0.043) & (B=0.072). Increased TSH levels were significant with having an increased E/A ratio (P=0.003) & (B=0.009). Significant predictors of systolic dysfunction were male sex, ST-elevation MI, current smokers, and alcohol consumption. Significant predictors of diastolic dysfunction were increasing age, increased BMI, male sex, and SCH.

Conclusion: SCH is prevalent among patients post-AMI and it is a significant predictor of diastolic dysfunction.