Effects of Triiodothyronine (T3) in Ischemic Heart Failure

Inclusion Criteria: * Aged 18-80 years, male or female; * Confirmed diagnosis of ischemic HF with left ventricular ejection fraction (LVEF) ≤ 40% (measured by echocardiography within 1 month of Screening); * Stable symptoms; NYHA class II-III without recent admission (1 month) for acute decompensation; * Receiving guideline-based standard HF therapies at the maximum tolerated doses for \>1 month. Patients on other beta-blockers will be switched to metoprolol succinate at equivalent doses for 3 weeks. * Presence of ICD for \>1 month or implantable cardiac resynchronization therapy defibrillator (CRT-D) for \>3 months * Understand and sign the informed consent form. Exclusion Criteria: * LVEF \> 40%; * Unremitting atrial fibrillation during the screening period or clinically significant ventricular tachycardia (on ICD interrogation); * Non-ischemic HF including hypertrophic cardiomyopathy, peripartum or chemotherapy-induced cardiomyopathy, other non-ischemic cardiomyopathies, constrictive pericarditis, significant and uncorrected valvular heart disease (severe regurgitation or severe stenosis or valvular disease requiring surgery), congenital heart disease, primary pulmonary hypertension or secondary severe pulmonary hypertension (≥ 70 mmHg); large pericardial or pleural effusions; right heart failure due to lung disease; * Recent admission (1 month) for acute decompensated HF; * Angina pectoris, cerebrovascular accident, myocardial infarction, revascularization (PCI or othe…