Tachycardia in hyperthyroidism: Not so common.

Area of Science:

• Endocrinology
• Cardiology

Background:

• The traditional association of hyperthyroidism with sinus tachycardia and widened pulse pressure (PP) is outdated.
• Current hyperthyroidism patients may not consistently exhibit these classic signs.

Purpose of the Study:

• To reassess the prevalence and variability of sinus tachycardia and widened PP in contemporary hyperthyroidism patients.
• To investigate the relationship between these clinical signs and the degree of hyperthyroidism.

Main Methods:

• Retrospective analysis of 248 adult outpatients with confirmed hyperthyroidism.
• Data included heart rate (HR), blood pressure (BP), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) levels.
• Exclusion of patients on medications affecting HR or BP.

Main Results:

• Tachycardia (HR >100 bpm) was present in 28.2% of patients, increasing with higher fT4 levels.
• A more lenient tachycardia definition (HR >90 bpm) was observed in 47.2%.
• Widened PP (>50 mmHg) was found in 64.1% and correlated with higher fT4 and BP.

Conclusions:

• Sinus tachycardia is not a common feature in present-day hyperthyroidism.
• Increased thyroid function testing likely identifies milder or asymptomatic thyrotoxicosis cases.
• Widened pulse pressure remains a prevalent clinical finding in hyperthyroidism.