P-wave dispersion in endogenous and exogenous subclinical hyperthyroidism.

Area of Science:

• Cardiology
• Endocrinology
• Thyroid Research

Background:

• Subclinical hyperthyroidism is associated with cardiac risks.
• P wave duration (Pmax) and P wave dispersion (PWD) can indicate paroxysmal atrial fibrillation risk.
• Thyroid hormone levels may influence cardiac electrophysiology.

Purpose of the Study:

• To measure Pmax and PWD in patients with subclinical hyperthyroidism.
• To investigate the relationship between Pmax, PWD, and thyroid hormone levels.
• To compare cardiac parameters in endogenous versus exogenous subclinical hyperthyroidism.

Main Methods:

• Electrocardiogram (ECG) recordings were used to measure Pmax and Pmin.
• PWD was calculated as Pmax - Pmin.
• Study included 71 patients with subclinical thyrotoxicosis and 69 healthy controls.

Main Results:

• Pmax and PWD were significantly elevated in both endogenous and exogenous subclinical hyperthyroidism groups compared to controls.
• No significant difference in Pmax and PWD was observed between endogenous and exogenous groups.
• Pmax and PWD showed a negative association with TSH levels.

Conclusions:

• Patients with subclinical hyperthyroidism exhibit prolonged Pmax and PWD.
• The findings suggest thyroid hormone levels, rather than the etiology of thyrotoxicosis, impact cardiac parameters.
• Elevated Pmax and PWD in subclinical hyperthyroidism may signify increased atrial fibrillation risk.