New-onset atrial fibrillation

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” AF do not require immediate cardioversion. Most patients will require medical therapy to control ventricular rate initially, and rhythm control subsequently.

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 activation and consequently ineffective atrial contraction.[1]Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on clinical practice guidelines. Circulation. 2024 Jan 2;149(1):e1-156. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000001193 http://www.ncbi.nlm.nih.gov/pubmed/38033089?tool=bestpractice.com

Electrocardiographic characteristics include: irregularly irregular R-R intervals (where atrioventricular conduction is not impaired); absence of distinct repeating P waves; irregular atrial activations also known as fibrillatory waves.[1]Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation: a report of the American College of Cardiology/American Heart Association Joint Committee on clinical practice guidelines. Circulation. 2024 Jan 2;149(1):e1-156. https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000001193 http://www.ncbi.nlm.nih.gov/pubmed/38033089?tool=bestpractice.com

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 Established atrial fibrillation.