Cardiac changes in subclinical and overt hyperthyroid women: retrospective study

Area of Science:

• Cardiology
• Endocrinology
• Thyroid Research

Background:

• Cardiac alterations in hyperthyroidism remain incompletely understood.
• Subclinical hyperthyroidism is often overlooked despite potential cardiac implications.

Purpose of the Study:

• To describe cardiac changes associated with subclinical and overt hyperthyroidism.
• To evaluate the clinical significance of subclinical hyperthyroid cardiac effects.

Main Methods:

• Retrospective analysis of 31 cardiopathic women with hyperthyroidism (19 subclinical, 12 overt).
• Exclusion criteria included euthyroid/hypothyroid status, amiodarone use, hypertension, rheumatic disease, and myocardial infarction.
• Cardiac parameters assessed included atrial fibrillation prevalence, left atrial dimension, heart rate, left ventricular end-diastolic volume, and left ventricular mass.

Main Results:

• Atrial fibrillation prevalence and left atrial dimension were similar in subclinical and overt hyperthyroidism.
• Hyperthyroid women exhibited larger left atrial dimensions compared to controls (P<0.001).
• Increased heart rate and reduced left ventricular end-diastolic volume were observed in both subclinical and overt hyperthyroidism; overt hyperthyroidism also showed increased left ventricular mass, correlated with free triiodothyronine levels.

Conclusions:

• Elevated heart rate and decreased left ventricular end-diastolic volume signify impaired diastolic function in both subclinical and overt hyperthyroidism.
• Overt hyperthyroidism is further complicated by left ventricular concentric hypertrophy.
• Subclinical hyperthyroidism warrants serious clinical consideration beyond a mere laboratory finding.