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[Serum thyroid hormone levels correlate with cardiac function and ventricular tachyarrhythmia in patients with
N Shimoyama1, T Maeda, T Inoue
1First Department of Internal Medicine, Medical College of Oita.
Insights
Thyroid hormones like free triiodothyronine (FT3) and reverse triiodothyronine (rT3) correlate with chronic heart failure severity. Lower FT3 and higher rT3 levels indicate worse cardiac function and predict ventricular tachycardia.
Area of Science:
- Endocrinology
- Cardiology
- Internal Medicine
Context:
- Chronic heart failure (CHF) is a complex condition affecting cardiac function.
- Thyroid hormones play a crucial role in cardiovascular regulation.
- The interplay between thyroid status and CHF severity requires further elucidation.
Purpose:
- To investigate the relationship between serum thyroid hormone levels and cardiac function in patients with chronic heart failure.
- To assess the correlation between thyroid hormone profiles (FT3, FT4, rT3) and clinical/echocardiographic parameters of heart failure severity.
- To determine if thyroid hormone levels can predict adverse cardiac events like ventricular tachycardia.
Summary:
- Serum levels of free triiodothyronine (FT3), free thyroxine (FT4), and reverse triiodothyronine (rT3) were measured in 41 CHF patients and 15 controls.
- Decreased FT3 and FT3/FT4 ratios, along with increased rT3, were associated with worse New York Heart Association (NYHA) class and reduced echocardiographic fractional shortening.
- Lower FT3 and higher rT3 levels were observed in patients with ventricular tachycardia, suggesting a role in arrhythmia prediction.
Impact:
- Serum thyroid hormone levels, particularly FT3 and rT3, can serve as quantitative biomarkers for assessing CHF severity.
- These hormonal profiles may aid in predicting the risk of ventricular tachycardia in heart failure patients.
- Findings suggest potential for thyroid hormone modulation as a therapeutic strategy in managing CHF.
Abstract:
The relationship between cardiac function and serum thyroid hormone levels was investigated in 41 patients with chronic heart failure (25 men and 16 women, mean age 63.7 +/- 11.1 years) and 15 normal subjects (5 men and 10 women, mean age 55.5 +/- 12.2 years). Patients with apparent thyroid disease were excluded from the study. All patients were evaluated according to the New York Heart Association (NYHA) classification using echocardiography, cardiothoracic ratios, mean daily heart rates calculated from ambulatory electrocardiograms (ECG), and ventricular tachyarrhythmias greater than triplets based on either Holter or ECG monitoring. The serum free triiodothyronine (FT3), free thyroxine (FT4), and reverse triiodothyronine (rT3) levels were measured. Decreased FT3 levels and FT3/FT4 ratios, and increased rT3 levels were associated with worse NYHA class. FT3/FT4 was positively and rT3 was negatively correlated with echocardiographical fractional shortening. FT3 and rT3 were negatively and positively correlated with mean daily heart rates, in contrast to known hypothyroid patients. Patients with ventricular tachycardia demonstrated significantly lower serum values of FT3 and FT3/FT4, and significantly higher values of rT3. Serum thyroid hormone levels can provide a quantitative index for evaluating the severity of chronic heart failure and predicting ventricular tachycardia.