Out of 20 subjects selected for refractory arrhythmias, amiodarone therapy (200mg/day) was efficacious in 85%. No statistically significant variations in electrocardiographic parameters (QTc) were observed; similarly, there was little evidence of side effects 1 year after initiation of treatment. These results were most likely due to the low daily dosage administered. We observed: 1) a significant increase in rT3 levels; 2) a decrease in TT3; 3) a uniform homeostasis of free fraction (FT3; FT4) These effects are all characteristic patterns of a "Low T3 Syndrome". The dosage of circulating amiodarone in 6 patients with borderline hormonal status (3 hyper-and 3 hypothyroidism) was not found to be an efficacious test for therapeutic monitoring. Identification of a statistically significant linear regression relationship between cumulative dose of amiodarone and rT3 levels may be a useful test in clinical practise for establishing more appropriate therapeutic dosages. Furthermore, it provides a guideline for threshold levels (maximum rT3=100-110ng/dl) which are in close association with several side effects.

Amiodarone and thyroid status in refractary arrythmias

A. Piffanelli
Primo
;
D. Pelizzola
Secondo
;
M. Giganti
Penultimo
;
1988

Abstract

Out of 20 subjects selected for refractory arrhythmias, amiodarone therapy (200mg/day) was efficacious in 85%. No statistically significant variations in electrocardiographic parameters (QTc) were observed; similarly, there was little evidence of side effects 1 year after initiation of treatment. These results were most likely due to the low daily dosage administered. We observed: 1) a significant increase in rT3 levels; 2) a decrease in TT3; 3) a uniform homeostasis of free fraction (FT3; FT4) These effects are all characteristic patterns of a "Low T3 Syndrome". The dosage of circulating amiodarone in 6 patients with borderline hormonal status (3 hyper-and 3 hypothyroidism) was not found to be an efficacious test for therapeutic monitoring. Identification of a statistically significant linear regression relationship between cumulative dose of amiodarone and rT3 levels may be a useful test in clinical practise for establishing more appropriate therapeutic dosages. Furthermore, it provides a guideline for threshold levels (maximum rT3=100-110ng/dl) which are in close association with several side effects.
Piffanelli, A.; Pelizzola, D.; Ricci, L.; Codecà, L.; Giovannini, G.; Giganti, M.; Colamussi, V.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1869743
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