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Abnormalities in pituitary thyroid axis function tests in patients with paroxysmal supraventricular arrhythmias
Hormone and Metabolic Research = Hormon- Und Stoffwechselforschung = Hormones Et Metabolisme
|February 1, 1987
Summary
Occult thyrotoxicosis, a mild thyroid overactivity, was identified in a small fraction of patients with paroxysmal supraventricular arrhythmias (PSVA). This finding highlights the importance of thyroid function tests in diagnosing arrhythmias.
Area of Science:
- Cardiology
- Endocrinology
- Internal Medicine
Background:
- Paroxysmal supraventricular arrhythmias (PSVA) can present without obvious cardiovascular causes.
- Thyroid dysfunction is a potential, though often overlooked, contributor to cardiac arrhythmias.
Purpose of the Study:
- To investigate the prevalence of
- occult thyrotoxicosis
- in patients presenting with PSVA.
- To assess the utility of thyroid hormone levels and TSH response to TRH in identifying subclinical thyroid overactivity.
Main Methods:
- Evaluated 60 consecutive patients with PSVA.
- Assessed serum free thyroxine (FT4), free triiodothyronine (FT3), and thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH).
- Excluded patients with overt cardiovascular disease and abnormal baseline thyroid function tests.
Main Results:
- Normal thyroid scintiscan and baseline thyroid hormone levels in most patients.
- Abnormal TSH response to TRH was observed in 10 patients (16.7%).
- Five patients (8.3%) demonstrated "occult thyrotoxicosis" characterized by elevated FT4/FT3 and abnormal TSH response.
Conclusions:
- A small proportion of PSVA patients may have underlying "occult thyrotoxicosis".
- Combined assessment of free thyroid hormones and TSH response to TRH is crucial for detecting this condition.
- Thyroid evaluation should be considered in the workup of unexplained PSVA.