7414 Is It Time for a New Risk Stratification Scoring System for Thyrotoxicosis Related Atrial Fibrillation?

Abstract Disclosure: A. Newman: None. L. Esmati: None. A.M. Solomon: None. A. Qureshi: None. R. Anketell: None. A 26-year-old female presented to emergency care with 6-months of palpitations, diarrhoea, and nervousness. She had exophthalmos and a goitre. Her ECG showed sinus tachycardia. Thyroid stimulating hormone was <0.01 mIU/l, free T4 84.9 pmol/l (12-22 pmol/l), and T3 42.1 pmol/l (3.1 -6.8 pmol/l). She had a raised ALT of 59 IU/L (10 - 35 IU/L) and ALP 155 IU/L (30 - 130 IU/L). Bone natriuretic peptide was 822 (<300 ng/L). Thyroid stimulating immunoglobulin was >100 IU/L (< 1.8 IU/L). She was managed as suspected Graves’ disease, with carbimazole 20mg once daily and propranolol 10mg three times daily. Despite treatment, her palpitations worsened. On representing, an ECG showed atrial fibrillation (AF) at 120 beats per minute. Her Burch-Wartofsky point scale (BWPS) of 35 did not meet thyroid storm criteria. Carbimazole was increased to 40mg once a day and propranolol to 30mg three times a day. She was anti-coagulated with low molecular weight heparin. An echocardiogram showed left atrial dilation but was otherwise normal. With up-titration of her anti-thyroid medication, she cardioverted to sinus rhythm. Her symptoms resolved, anticoagulation was stopped, and she was discharged. The association between hyperthyroidism and AF is well known but is often undermined. Thyrotoxicosis related AF should be considered seriously and early on in thyroid disease, due to AF’s association with stroke and heart failure. In myocardial cells T4 affects depolarisation and refractory periods leading to dysrhythmias. However, AF rarely presents in young healthy individuals. This patient however had several risk factors for AF including atrial dilation, her demographic, deranged liver function tests, and a smoking history. These should have been considered on initial presentation. Studies show atrial dilatation causes atrial fibrosis and electrical misfiring, predisposing to AF. Additionally, she was Afro-Caribbean, with a strong hyperthyroid family history. A similar case was reported with hyperthyroid related AF in a 10-year-old Afro-Caribbean boy. He too had a strong family history, suggesting a genetic demographic predisposition. Within a retrospective cohort, smoking was associated with thyroid disease AF, due to oxidative stress, inflammation, and atrial fibrosis. Liver dysfunction although common in Graves’ disease, has also been found to predict new onset AF. The patient was conservatively treated on first presentation. Previous thyrotoxicosis or untreated/partially treated thyroid disease can further predispose to AF due to cardiac remodelling. We propose a development of a risk stratification score like BWPS for AF in thyroid disease using risk factors such as those forementioned. This will guide clinical management towards more aggressive earlier treatment. It will improve care, prevent readmissions, and further complications associated with atrial fibrillation such as stroke. Presentation: 6/3/2024