MEDizzy - An 80-year-old woman was admitted to your service for

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Cardiology

An 80-year-old woman was admitted to your service for dizziness. Cardiac monitoring initially revealed atrial fibrillation with rapid ventricular response. Her ventricular rate was controlled with a beta-blocker. An echocardiogram revealed an enlarged left atrium and an ejection fraction of 50%. No evidence of diastolic heart dysfunction was noted. She is now asymptomatic, with blood pressure 130/80, heart rhythm irregularly irregular, and heart rate around 80/minute. Which of the following is the best management strategy of this patient’s arrhythmia?

ExplanationMost patients with atrial fibrillation tolerate rate control without loss of exercise tolerance, increased morbidity, or increased mortality. “Rate control” means that the heart rate is slowed but the patient remains in atrial fibrillation. Cardioversion (either electrical or mechanical) is reserved for those with symptoms (troubling palpitations, exertional dyspnea) despite rate control alone. If cardioversion is required, the patient is usually treated with an antiarrhythmic agent (type 1 antiar-rhythmic or amiodarone), with its own side effects. Many patients who undergo cardioversion are continued on warfarin because of the high risk (up to 70%) of going back into atrial fibrillation despite antiarrhythmic drug treatment. Cardioversion, therefore, does not obviate the risks associated with long-term warfarin use. This patient’s left atrial enlargement makes it unlikely that she would remain in sinus rhythm after cardioversion. Therefore, rate control with prolonged anticoagulation is appropriate. Indefinite anticoagulation with warfarin is necessary.