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Cardiac function in hypothyroid children: effect of replacement therapy
R Bhupathi1, S S Kothari, A K Gupta
1Department of Pediatrics, All India Institute of Medical Sciences, New Delhi 110 029, India.
Insights
Children with primary hypothyroidism show subtle cardiac changes that improve with L-thyroxine treatment. Echocardiography revealed altered systolic and diastolic functions, which normalized after therapy, indicating reversible myocardial dysfunction.
Area of Science:
- Pediatric Cardiology
- Endocrinology
- Cardiovascular Physiology
Background:
- Primary hypothyroidism in children can affect cardiac function.
- Early diagnosis and treatment are crucial for preventing long-term complications.
Purpose of the Study:
- To prospectively evaluate cardiac function in children with primary hypothyroidism.
- To assess the impact of L-thyroxine replacement therapy on myocardial function.
Main Methods:
- Prospective study of 20 children (6 months - 14 years) with primary hypothyroidism.
- Comprehensive cardiac assessment including ECG, echocardiography, and phonocardiography.
- Evaluation of systolic and diastolic functions before and after L-thyroxine therapy.
Main Results:
- Systolic time intervals and isovolumic relaxation time significantly improved post-therapy (p <0.001).
- Ejection fraction and velocity of circumferential fiber shortening showed no significant change.
- Pericardial effusion resolved in 7 out of 10 children after treatment.
Conclusions:
- Children with primary hypothyroidism exhibit reversible alterations in myocardial function.
- L-thyroxine therapy effectively normalizes cardiac function and resolves pericardial effusion.
- This study highlights the importance of cardiac monitoring in pediatric hypothyroidism.
Objective:
To evaluate prospectively cardiac function in children with primary hypothyroidism before and after replacement therapy with L-thyroxine.
Design:
Prospective clinical and laboratory cardiac evaluation of children with hypothyroidism before and after therapy.
Setting:
Hospital based.
Subjects:
20 consecutive children aged 6 months - 14 years with primary hypothyroidism.
Methods:
Assessment of cardiac status by clinical, radiological, ECG, echocardiography, M-mode and 2 dimensional echo-Doppler study and phonocardiography for systolic and diastolic functions and structural anomalies.
Results:
Indices of myocardial contractility like ejection fraction (EF), velocity of circumferential fibre shortening (VCF) did not change with therapy. However, systolic time intervals, both left ventricular (before therapy 0.32+/-0.03 msec; after therapy 0.25+/-0.03 msec; p <0.001) showed a significant change. In diastolic functions, isovolumic relaxation time fell from 62+/-9 msec before therapy to 50+/-5 msec after therapy (p <0.001). Pericardial effusion was found in 10 children before treatment which disappeared in 7 following therapy.
Conclusion:
Subtle evidence of alteration of myocardial function is thus seen in children with primary hypothyroidism which reverses with treatment.