Iatrogenic cardiac arrest during thyroid storm

Introduction: Thyroid storm is a life-threatening condition with often severe cardiac implications. Correct treatment choices can vary depending on underlying cardiac systolic function. Case description: We present a case of a 47-year-old male with untreated Grave's disease who presented with a thyroid storm. After propranolol administration, he experienced a cardiac arrest with the return of spontaneous circulation after cardiopulmonary resuscitation. Further evaluation revealed severe thyroid-induced cardiomyopathy with left ventricular ejection fraction of 15-20%, which had decreased from 60-65% over one year. The patient was discharged home on hospital day 8 after an unremarkable ischaemic work-up. He experienced a full cardiac systolic function recovery with an ejection fraction of 60-65% at the 90-day follow-up. Conclusion: Thyroid storm can present with overt or subclinical heart failure. Prompt evaluation of cardiac systolic function with a transthoracic echocardiogram before beta-blockade and the use of shorter-acting beta blockers can prevent devastating suppression of myocardial function. LEARNING POINTS: Despite being first-line therapy, beta blockers can be beneficial or devastating in thyroid storm patients depending on the presence of low cardiac output or high cardiac output heart failure.Clinical awareness, prompt echocardiography and the use of shorter half-life beta blockers can prevent rapid cardiac deterioration in thyroid storm patients.