CONTEXT: Patients with amiodarone-induced thyrotoxicosis (AIT) and left 
ventricular (LV) systolic dysfunction have a high mortality rate. Usually, 
medical therapy is the first choice for AIT patients, whereas the role of the 
thyroidectomy is unsettled.
OBJECTIVE: The objective of the study was to evaluate the effect of a total 
thyroidectomy on cardiac function and survival of AIT patients with severe LV 
systolic dysfunction.
DESIGN: This was a retrospective cohort study.
SETTINGS: The study was conducted at a tertiary university center.
PATIENTS: All AIT patients (n=24; nine patients with type 1 AIT, 15 patients 
with type 2 AIT) referred to the Department of Endocrinology and submitted to a 
total thyroidectomy at the Department of Surgery, both at the University of 
Pisa, during the years 1997-2010.
INTERVENTION: The intervention was a total thyroidectomy.
MAIN OUTCOME MEASURE: LV ejection fraction (EF) after the thyroidectomy and 
survival in December 2011 were measured.
RESULTS: All enrolled patients had previously undergone to medical treatment for 
AIT, as appropriate, without achieving euthyroidism. Patients with moderate to 
severe LV systolic dysfunction (EF<40%, group 1, n=9) or with mild systolic 
dysfunction (40%≤EF≤50%, group 2, n=5) were compared with patients with normal 
systolic function (EF>50%, group 3, n=10). Two months after thyroidectomy, under 
levothyroxine replacement therapy, LVEF improved in patients with LV systolic 
dysfunction, particularly in those of group 1, in whom it increased from 
28.2±7.2 to 38.3±6% (P=0.007). On the contrary, LVEF did not significantly 
change in group 3 (from 57.1±3.0 to 59.8±6.6%, P=0.242). The mean follow-up was 
67±42 months. No death occurred during and 2 months after surgery. One death 
occurred in one patient of group 1, 30 months after the thyroidectomy, due to 
acute myocardial infarction. No patient had relevant complications of 
thyroidectomy.
CONCLUSIONS: Total thyroidectomy, by rapidly restoring euthyroidism, may improve 
cardiac function and reduce the risk of mortality in AIT patients with severe LV 
dysfunction.