Amiodarone-induced thyrotoxicosis: left ventricular dysfunction is associated with increased mortality.

Area of Science:

• Endocrinology
• Cardiology
• Pharmacology

Background:

• Amiodarone-induced thyrotoxicosis (AIT) poses significant management challenges, particularly in patients with pre-existing heart conditions.
• Thyrotoxicosis in these patients can exacerbate morbidity and mortality.
• Comparing AIT with other common thyrotoxicosis forms is crucial for understanding its distinct clinical profile.

Purpose of the Study:

• To compare the clinical outcomes and hormone profiles of patients with AIT against those with Graves' thyrotoxicosis and toxic multinodular goitre (MNG).
• To identify predictors of mortality in AIT patients.

Main Methods:

• A retrospective study was conducted on patients with AIT over a 12-year period.
• Clinical data and hormone profiles were collected and analyzed.
• Patient groups included AIT (n=60), Graves' thyrotoxicosis (n=49), and toxic MNG (n=40).

Main Results:

• All groups showed suppressed TSH levels, with no significant intergroup differences.
• Free thyroxine (T4) levels were elevated in AIT and Graves' disease compared to MNG.
• Free triiodothyronine (T3) levels were significantly higher only in Graves' disease.
• A mortality rate of 10.0% was observed in the AIT group, significantly higher than other groups.
• Amiodarone treatment was the strongest predictor of death; severe left ventricular dysfunction was significantly associated with mortality in AIT patients.

Conclusions:

• Amiodarone-induced thyrotoxicosis exhibits distinct clinical characteristics compared to Graves' disease and toxic MNG.
• Severe left ventricular dysfunction is a critical factor associated with increased mortality in patients with AIT.
• Understanding these differences is vital for effective management and improved patient outcomes.