New onset atrial fibrillation (AF) is atrial fibrillation identified for the first time by an electrocardiogram or other electrocardiographic rhythm recording device, such as ambulatory or inpatient monitoring.
There is overlap between “new onset,” “acute,” and “first identified” atrial fibrillation, but each represents a distinct clinical presentation with unique features mandating different assessments and management. Typical symptoms associated with new onset atrial fibrillation include palpitations, a sense of the heart racing, an irregular pulse, fatigue, lightheadedness, increased urination, weakness, and mild shortness of breath. More severe symptoms and signs include dyspnea, angina, hypotension, and presyncope. Infrequently, myocardial infarction, syncope, or pulmonary edema may occur. In addition, some patients present with an embolic event (particularly stroke) or the insidious onset of right-sided heart failure (as manifested by peripheral edema, weight gain, and ascites).
Occasionally, the first detection of AF will occur incidentally and in the absence of symptoms at the time or during a routine examination or on an electrocardiogram obtained for other reasons, but such episodes may be present for extended periods or simply missed on prior examinations. Rarely, a patient with arterial thromboembolism is found only in retrospect to have new onset atrial fibrillation. Episodes at presentation can be paroxysmal and stop spontaneously, persistent and stop only with cardioversion, or permanent and present for prolonged periods.
This topic will address the following management decisions, which need to be made soon after a patient presents with new onset AF:
- Is cardioversion indicated and if so should it be urgent?
- When and how should rate control be carried out?
- Who should be anticoagulated immediately and how?
- Does the patient need hospitalization?
- Are there any correctable causes of atrial fibrillation?
- What should be done with the patient who spontaneously converts to sinus rhythm?