New-onset atrial fibrillation (AF) is a new or first detectable episode of a chaotic and irregular atrial arrhythmia. Prevalence increases progressively with age.
AF causes significant morbidity and mortality including palpitations, dyspnea, angina, dizziness or syncope, and features of congestive heart failure, tachycardia-induced cardiomyopathy, stroke, and death.
ECG shows absent P waves, presence of fibrillatory waves, and irregularly irregular QRS complexes.
Most patients presenting with new-onset or “acute” atrial fibrillation (AF) do not require immediate cardioversion. Most patients will require medical therapy to control ventricular rate.
Patients who develop hemodynamic compromise should have immediate direct current cardioversion.
If the precise timing of the onset of AF is unclear, a transesophageal echocardiogram must be performed to exclude left atrial clots before cardioversion.
AF is a supraventricular tachyarrhythmia with uncoordinated atrial activiation and consequently ineffective atrial contraction.
Electrocardiographic characteristics include: irregularly irregular R-R intervals (where atrioventricular conduction is not impaired); absence of distinct repeating P waves; irregular atrial activations.
New-onset AF is defined as a new onset or a first detectable episode of AF, whether symptomatic or not. This topic will concentrate on new-onset AF in the nonvalvular and nonsurgical settings. For more information on paroxysmal and asymptomatic new-onset AF see Chronic atrial fibrillation.
History and exam
Key diagnostic factors
- irregular pulse rate
Other diagnostic factors
- elevated jugular venous pressure
- added heart sounds
- evidence of stroke
- increasing age
- orthostatic hypotension
- diabetes mellitus
- heart failure
- valvular and structural heart disease
- coronary artery disease and acute coronary syndromes
- other atrial arrhythmias
- sepsis and critical illness
- cardiac or thoracic surgery
- hypoxic pulmonary conditions
- alcohol consumption
- inflammatory disorders
- excessive exercise
- cancer and chemotherapy
1st investigations to order
- serum electrolytes
- cardiac biomarkers
- thyroid function tests
- transthoracic echocardiogram
- transesophageal echocardiogram (TEE)
Investigations to consider
- electrophysiologic study
- exercise stress tests
hemodynamically stable with left atrial thrombus, or presence of thrombus unknown/duration of AF unknown
hemodynamically stable without left atrial thrombus: symptom onset <48 hours
hemodynamically stable without left atrial thrombus: symptom onset ≥48 hours
hemodynamically stable without left atrial thrombus: asymptomatic
- Atrial flutter
- Wolff-Parkinson-White syndrome
- Atrial tachycardia
- Atrial fibrillation: diagnosis and management
- 2021 European Heart Rhythm Association practical guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation
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