Abstract
BACKGROUND: Thyrotoxicosis can lead to high-output cardiac failure, and although beta-blockers have a relative contraindication in decompensated congestive heart failure, they are commonly used in thyrotoxicosis to control hypersympathetic activity. CASE SUMMARY: This is the case of a 38-year-old female who arrived with a thyroid storm, atrial fibrillation, and volume overload in physical examination. Echo revealed severely reduced left ventricular systolic function with normal diastology. She started on esmolol and successfully transitioned to propranolol. DISCUSSION: This case highlights the need to tailor beta-blocker therapy based on the underlying cause of left ventricular dysfunction, particularly when sustained tachycardia and decreased systemic vascular resistance are the main drivers of thyrotoxic cardiac failure. TAKE-HOME MESSAGE: Suspect thyrotoxic cardiac failure, especially in the setting of normal diastology, and consider starting BB.