Review Question - QID 104176

This patient's EKG shows atrial fibrillation. Hyperthyroidism is an important cause of atrial fibrillation and should be evaluated for by checking a TSH level.

Atrial fibrillation is the most common cardiac arrhythmia and typically is asymptomatic. However, patients may present acutely with palpitations, weakness, chest discomfort, and shortness of breath. EKG will reveal an irregularly irregular rhythm with absent P-waves and narrow QRS complexes. The ventricular rate may vary, but is frequently increased. Acute atrial fibrillation may result from cardiac, pulmonary, metabolic, and drug-related causes, several of which are listed in Illustration A.

Guiterrez and Blanchard review the treatment of atrial fibrillation. Rate control is the preferred management option in most patients. Rhythm control is an option for patients in whom rate control cannot be achieved or who have persistent symptoms despite rate control. The current recommendation for strict rate control is a resting heart rate of less than 80 beats per minute. Administration of anticoagulation is guided by the CHADS2/CHA1DS2-VASC score and time since onset of arrhythmia.

Wazni et al. review the guidelines for catheter ablation for atrial fibrillation. They stress that ablation is performed for symptom relief and to improve the quality of life. Ablation has not been proven to decrease the risk of stroke or improve longevity. Recurrence of atrial fibrillation is common and may require another trial of antiarrhythmic drugs or a second ablation. Even if the ablation is successful, discontinuing anticoagulation must be approached cautiously.

Figure A is an EKG showing atrial fibrillation. Note the irregularly irregular rhythm and absence of P waves. Illustration A outlines the various etiologies of atrial fibrillation. Illustration B explains the CHADS2 score for determination of oral anticoagulation for patients with atrial fibrillation.

Incorrect Answers:
Answer 1: Atrial fibrillation is not associated with Cushing's syndrome.
Answer 2: While alcohol may cause atrial fibrillation, this patient does not appear to be intoxicated and denies a history of drinking alcohol.
Answer 3: Chest x-ray would be useful for identifying pneumonia, which does not fit this patient's clinical presentation and is not associated with the development of atrial fibrillation.
Answer 5: Catecholamine surges such as from a pheochromocytoma can cause atrial fibrillation, but it is much less common than hyperthyroidism.