What is Paroxysmal Atrial Fibrillation?
Paroxysmal atrial fibrillation is AF that terminates spontaneously within 7 days, with most episodes self-resolving within 48 hours. 1
Core Definition
Paroxysmal AF represents a specific temporal pattern of atrial fibrillation characterized by:
- Self-terminating episodes within 7 days (or with intervention), distinguishing it from persistent AF which continues beyond 7 days 1
- Most episodes resolve within 24-48 hours in clinical practice 1
- Episodes can last seconds to hours and may recur repeatedly over years 1
- Spontaneous termination is the key feature - whether the episode ends on its own or requires intervention (cardioversion or medication) does not change the classification as paroxysmal 1
Clinical Context and Classification
The temporal classification system distinguishes paroxysmal AF from other patterns:
- First-detected AF: Any initial presentation regardless of duration or symptoms, which may be either paroxysmal or persistent 1, 2
- Recurrent AF: Two or more episodes, which can be paroxysmal or persistent 1
- Persistent AF: Episodes sustained beyond 7 days 1, 2
- Permanent AF: Accepted ongoing rhythm where cardioversion has failed or is not attempted 1, 2
Important Clinical Caveats
Categories are not mutually exclusive - the same patient may experience both paroxysmal and persistent episodes at different times, and should be categorized by their most frequent presentation pattern 1, 2
Episodes lasting ≥30 seconds without a reversible cause qualify for the diagnosis, though this threshold may vary in specific clinical contexts involving symptomatic patients or when assessing therapeutic interventions 1
Secondary AF should be considered separately - AF occurring during acute MI, cardiac surgery, pericarditis, myocarditis, hyperthyroidism, pulmonary embolism, or pneumonia typically resolves with treatment of the underlying condition and does not represent true paroxysmal AF 1, 2
ECG Documentation Requirements
ECG confirmation is required to establish the diagnosis and initiate risk stratification and management, which can include 12-lead ECG, single-lead devices, or multiple-lead devices that provide an ECG recording 1
The surface ECG shows:
- Absence of discernible, regular P waves 1
- Irregular ventricular activation with no specific pattern to RR intervals (in absence of AV block) 1
Epidemiology
Paroxysmal AF comprises 25-62% of all AF cases with similar underlying causes to sustained AF 3, 4
AF affects approximately 2.2-2.3 million people in North America and 4.5 million in the European Union, with paroxysmal AF representing a substantial proportion 1