Gated SPECT findings revealing diastolic dysfunction in acute hypothyroidism

Area of Science:

• Cardiology
• Nuclear Medicine
• Endocrinology

Background:

• Acute hypothyroidism can affect cardiac function.
• Left ventricular (LV) function assessment is crucial in endocrine disorders.
• Gated SPECT is a valuable tool for evaluating myocardial performance.

Purpose of the Study:

• To assess left ventricular (LV) function using gated SPECT in patients with acute hypothyroidism.
• To evaluate the impact of thyroxine replacement therapy on LV function in these patients.

Main Methods:

• Gated SPECT with Tc-99m sestamibi was performed on 38 hypothyroid patients and 40 controls.
• LV volumes, ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), and time to peak filling (TTPF) were quantified.
• Myocardial wall thickening and motion were assessed in 5 segments.

Main Results:

• Hypothyroid patients showed decreased PFR and prolonged TTPF compared to controls (P < 0.05).
• Thyroxine therapy significantly increased LV end-diastolic volume (EDV) and PFR in follow-up patients (P < 0.05).
• No significant differences in systolic wall thickening or motion were observed.

Conclusions:

• Gated SPECT identified diastolic dysfunction in acute hypothyroidism, characterized by reduced PFR and prolonged TTPF.
• Thyroxine replacement therapy demonstrated potential to improve these diastolic parameters.