Endocrine Abstracts (2017) 49 EP1212 | DOI: 10.1530/endoabs.49.EP1212

Atrial flutter with 1:1 atrioventricular conduction: An uncommon cardiac manifestation of hyperthyroidism

Amal Rached, Mariem Yazidi, Imen Sakka, Ons Rejeb, Nedia Khessairi, Malika Chihaoui & Hedia Slimane


La Rabta, Tunis, Tunisia.


Introduction: Atrial flutter (AFL) is a rapid, regular atrial tachyarrhythmia that occurs most commonly in patients with underlying structural heart disease. Patients with tachyarrythmias as a result of thyroid storm have been typically treated with beta-blockers to decrease the heart rate and alleviate beta-receptor mediated symptoms. We report an unusual case of AFL with 1:1 atrioventricular (AV) conduction.

Case report: Patient H, M 45 years old was admitted to our hospital with Graves Disease. He presented with typical symptoms which included tiredness, shaking, palpitations and opthalmopathy. He had lost 36 pounds over 3 months. He had a heart rate of 280/min, blood pressure of 130/80 mmHg, a moderate sized goitre without signs of right heart failure. An electrocardiogram revealed atrial flutter with 1:1 (AV) conduction. The echocardiogram showed a preserved internal dimension and overall normal systolic function. The diagnosis of hyperthyroidism was confirmed: Thyroid stimulating hormone: 0.002 mIU/l, Free T4: 3.52 ng/dl (0.7–1.5). He was treated with propranolol 60 mg/day and thiamazole 40 mg/day. He was placed on anticoagulation with warfarin for a target INR of 2–3. We performed a linear radiofrequency ablation and he reverted to sinus rhythm. His symptoms improved and he was discharged 1 week later.

Conclusion: This case report shows that AFL with 1:1 AV conduction may be observed in patients with hyperthyroidism and rapid supraventricular tachycardia.

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