hypothyroidism myxedema heart disease https://github.com/monarch-initiative/mondo/issues/8513 A rare complication of hypothyroidism characterized by unexplained heart failure refractory to conventional treatment. MEDGEN:526137 Myxedema heart disease is a potentially fatal syndrome that encompasses an enlarged cardiac silhouette, pericardial effusions, and electrocardiographic change: bradycardia, low-voltage, conduction blocks, ST changes, T-wave inversions, and arrhythmias. It is is potentially reversible with thyroid hormone (TH) administration. PMID:36225224 MONDO:1010108 UMLS:C0221048