Abstract:
Background: The prevalence of thyrotoxic cardiomyopathy (TCM) in hospitalized patients with heart failure and its recovery are unknown. Objectives: To determine the prevalence of TCM and reversible TCM in hospitalized patients with heart failure and to determine factors associated with TCM. Methods: We retrospectively reviewed 90 consecutive patients who were hospitalized with heart failure and thyrotoxicosis between 2002 and 2017. We excluded 26 patients because of significant coronary artery disease (n=2), severe aortic stenosis (n=1), severe primary mitral valve diseases (n=4), abnormal coronary artery (n=1), and absence of echocardiographic report during admission (n=18). 64 patients were included in the study. TCM was defined as LV ejection fraction (LVEF) ≤ 55%. Complete reversible TCM was defined as LVEF > 55%. Partial reversible cardiomyopathy was defined as improvement of LVEF > 10% and LVEF ≤ 55%. Results: Of 82 hospitalized patients with heart failure and thyrotoxicosis, 64 patients had complete echocardiographic studies for analysis. Of 64 patients, 12 (19%) patients had heart failure with reduced EF (HF-rEF) and 33 (58% female, age 46 ±15 years) patients (52%) had thyrotoxic cardiomyopathy (TCM). Prevalence of TCM is 0.9% of all heart failure hospitalized patient. In those with TCM, a mean LVEF =42%, Of 33 patients with TCM, 14 had follow-up complete echocardiographic studies for analysis. Of 14 patients, 8 patients (57%) had reversible TCM over a mean follow-up of 19 (1-79) months. Of 8 patients, 7 had complete recovery (LVEF>55%) while 1 had partial recovery. Hemoglobin, White blood cell, serum creatinine, bicarbonate, and Tricuspid annular plane systolic excursion (TAPSE) were associated with thyrotoxic cardiomyopathy (Odd ratio = 1.35 (95% CI 1.01-1.79 ; p=0.043), 1.01 (95% CI 1.01-1.02 ; p=0.004), 16.55 (95% CI 2.14-128.02 ; p=0.07), 0.85 (95% CI 0.73-0.98 ; p=0.028), and 0.67 (95% CI 0.46-0.98 ; p=0.037), respectively). Conclusions: To our knowledge, this report is the largest study in hospitalized patients with thyrotoxicosis and heart failure. Thyrotoxicosis cardiomyopathy (TCM) was present in half of patients who were hospitalized with heart failure and thyrotoxicosis. About 57% of those patients with TCM had recovery of LV systolic function over a median follow-up of 19 months. These findings underscore the importance of identifying hyperthyroid or thyrotoxicosis state in patients with heart failure since anti- thyroid therapy significantly lead to reversible heart failure syndrome and LV systolic dysfunction.