Endocrine Abstracts

Presentation: A 32-year-old woman was brought to the Emergency Department following an out-of-hospital cardiac arrest. CPR was started by a neighbour and on arrival, she was found to be in ventricular fibrillation (VF). She received 4 DC-shocks and reverted to atrial fibrillation with fast ventricular rate and staged a full cognitive and haemodynamic recovery. She had a 10-year history of Graves’ thyrotoxicosis for which she was on Carbimazole but remained uncontrolled due to non-compliance related to ongoing mental health and social issues. She was admitted to the Intensive Care Unit and was stabilised with Propylthiouracil, Lugol’s iodine, hydrocortisone and beta blockers. A definite diagnosis of thyroid storm was difficult in view of the post-cardiac arrest state and mental health background.

Investigations: Echocardiogram demonstrated a floppy prolapsed anterior mitral valve and moderate mitral regurgitation, dilated left ventricle (LV) with preserved LV function. Cardiac MR showed no evidence of scarring and coronary arteries were patent on CT angiogram.

Follow up: She remained stable and was euthyroid on block and replacement therapy, beta-blockers and anticoagulants.

Discussion: (a) Why did she have VF?: Single mitral leaflet prolapse and uncontrolled hyperthyroidism on their own have rarely been linked to VF although the latter is known to lower its threshold. Since structural cardiac pathology and channelopathy were excluded, the multidisciplinary opinion was that VF may have resulted from a combination of uncontrolled thyrotoxicosis and mitral valve prolapse (b) Management plan: The consensus is to proceed with mitral valve replacement, followed by cardiac re-assessment for ICD implantation. During this time stable euthyroidism would be maintained to lower the threshold of VF. Once the cardiac condition is stable, definitive therapy for thyrotoxicosis would be radioiodine administration, is in keeping with patient’s choice.