Review Question - QID 204081

In a patient with atrial fibrillation or tachycardia secondary to hyperthyroidism, the initial appropriate treatment is a beta blocker if that patient is stable.

Atrial fibrillation occurs when conduction in the atria fires in a continuous chaotic pattern resulting in an irregular, rapid ventricular rate. There are multiple causes including coronary artery disease, myocardial infarction, hypertension, mitral valve disease, pericarditis, pulmonary disease, alcohol intake, and stress. Another cause is hyperthyroidism. Clinically patients present with palpitations, dizziness, angina, and an irregular pulse. On EKG, the clinician should look for irregular RR intervals and tachycardia. Treatment depends on whether the patient is stable or unstable. In the unstable patient, immediate electrical cardioversion to sinus rhythm is indicated. In a stable patient, treatment focuses on rate control (target 60-100) with beta blockers or calcium channel blockers. After rate is controlled, rhythm can be addressed with cardioversion.

Reid and Wheeler discuss diagnosis and treatment of hyperthyroidism. The most common cause of hyperthyroidism is Graves' disease. Other causes include thyroiditis, toxic multinodular goiter, toxic adenomas, and medication side effects. Patients can be treated with radioactive iodine, antithyroid drugs, or surgery. New therapies are under investigation.

Gutierrez and Blanchard discuss diagnosis and treatment of atrial fibrillation. Atrial fibrillation is the most common cardiac arrhythmia. It impairs cardiac function and increases the risk of stroke. The key treatment issue includes the decision when to restore normal sinus rhythm, when to control rate only, and how to prevent thromboembolism. Rate control is the preferred management option in most patients.

Image A depicts the classic irregularly irregular tachycardia indicative of atrial fibrillation. Note the absence of P waves.

Incorrect Answers:
Answer 1: Emergent cardioversion is indicated in management of atrial fibrillation when the patient is not stable. However, this patient is stable and could be treated with a beta blocker.
Answer 3: Administration of amiodarone is used in the treatment of post myocardial infarction arrhythmias such as ventricular tachycardia but would not be indicated in this case.
Answers 4 and 5: These are potential options in the management of Grave's hyperthyroidism but would not immediately address the patient's chief complaint which is palpitations secondary to atrial fibrillation and tachycardia.