Paroxysmal atrial fibrillation

Editors-In-Chief: C. Michael Gibson, M.S., M.D.[mailto:mgibson@perfuse.org] and Ann Slater[mailto:aslater@perfuse.org], R.N., B.S.N.

Related Key Words and Synonyms: PAF, paroxysmal AF

Overview
PAF is defined as recurrent episodes of atrial fibrillation that terminate spontaneously in less than 7 days. Oftentimes it terminates within 24 hours.

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History and Symptoms
The most common symptom is palpitations. Often the patient describes an intermittent fluttering sensation in the chest. Less common symptoms include dizziness or lightheadedness, syncope, weakness, shortness of breath and chest pain. The patient may be asymptomatic, and the diagnosis may only be picked up on a screening EKG.

Vital Signs
The pulse may be irregularly irregular if the patient is sustaining an active episode of paroxysmal atrial fibrillation.

Electrolyte and Biomarker Studies
The patients thyroid function tests should be checked to exclude hyperthyroidism. Hypokalemia should be excluded.

Electrocardiogram
Often the patient is in normal sinus rhythm. When they are in paroxysmal atrial fibrillation, the following findings are present:


 * 1) Absent P waves
 * 2) Irregularly irregular ventricular response rate. Regular RR intervals are possible in the presence of AV block or interference due to ventricular or junctional tachycardia.
 * 3) An atrial rate that ranges from 400 to 700 BPM.
 * 4) Sometimes lead V1 may look as though there is atrial flutter. This may be because the electrode overlies a portion of the RA with rhythmic activity.
 * 5) Some authors believe that fine f waves (<.5 mm) are associated with coronary artery disease and that coarse F waves are associated with LA enlargement and rheumatic heart disease.
 * 6) The ventricular rate is usually between 100 and 180 BPM.
 * 7) If the atrial rate is greater than 200 BPM, then consider WPW or an accessory pathway.
 * 8) In the presence of AV junctional disease, the ventricular rate may be below 70 bpm.
 * 9) A rapid, irregular, sustained, wide-QRS-complex tachycardia strongly suggests AF with conduction over an accessory pathway or AF with underlying bundle-branch block.
 * 10) Complete AV block is indicated by a slow ventricular rhythm with a regular RR interval.
 * 11) In patients with electronic pacemakers, diagnosis of AF may require temporary inhibition of the pacemaker to expose atrial fibrillatory activity.
 * 12) Differential diagnosis includes an EKG artifact such as a tremor. The oscillations in this case are largest in the limb leads.

Holter Monitoring
Ambulatory event or Holter montoring is a cost effective tool that maybe considered. It provides a view of 2-3 leads over an extended time period, and sometimes is used as a diagnostic tool for the assessment of PAF.

Holter Monitoring Is Useful Article

Chest X Ray
While chronic atrial fibrillation is associated with an enlarged left atrial size, paroxysmal atrial fibrillation is generally not associated with an increase in left atrial size.

Acknowledgements
The content on this page was first contributed by: C. Michael Gibson, M.S., M.D.

Contributors
Ann Slater