Paroxysmal atrial fibrillation
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●Paroxysmal (ie, self-terminating or intermittent) atrial fibrillation (PAF) is defined as AF that terminates spontaneously or with intervention in less than seven days. This classification applies to episodes of AF that last more than 30 seconds and that are unrelated to a reversible cause.
If the AF is secondary to cardiac surgery, pericarditis, myocardial infarction, hyperthyroidism, pulmonary embolism, pulmonary disease, or other reversible causes, therapy is directed toward the underlying disease as well as the AF.
●The recurrence rate of AF is high in patients who present with PAF. The incidence in different reports has ranged from 70 percent at one year (without antiarrhythmic therapy) to 90 percent at four years to 60 to 65 percent at five to six years. These estimates almost certainly represent an underestimation of the true incidence.
●The percent of patients with PAF who progress to persistent or permanent AF increases with time. In different reports, the rate of progression to permanent AF was 8, 12, 18, and 25 percent at one, two, four, and five years, respectively.
●The risk of embolization with frequent and prolonged episodes of PAF may be similar to the risk in patients with persistent or permanent AF. However, data are not conclusive. We suggest an approach to antithrombotic therapy similar to that in the broad group of patients with AF, although recommendations should be individualized to the specific patient.
●The management of the arrhythmia in patients with PAF is similar to that for the general population of patients with AF.
There are two components to the management of the abnormal rhythm in patients with PAF:
●Acute control of the heart rate, usually with a beta blocker or calcium channel blocker (verapamil or diltiazem) or, if the patient has heart failure or hypotension, digoxin.
●Unless PAF reverts spontaneously, electrical cardioversion in patients who are hemodynamically unstable and either electrical or pharmacologic cardioversion in patients who are hemodynamically stable but have unacceptable symptoms and in patients with a first-detected episode of AF .
Prevention of recurrence
There are no data suggesting that preventing episodes of AF with any intervention reduces mortality, including the subset of patients with PAF. Thus, the decision to start antiarrhythmic drug therapy in patients with PAF is similar to that in the general population of patients with AF.
Patients with frequent or highly symptomatic PAF may require pharmacologic or nonpharmacologic therapy to prevent recurrence. The choice of therapy is often determined by the clinical setting as well as patient preference.
Catheter-based pulmonary vein isolation (PVI) is generally viewed as being more effective than antiarrhythmic medications. It has been increasingly used for prevention of PAF episodes and adopted as second-line therapy when antiarrhythmics have failed． Whether PVI should be considered first-line therapy has been a subject of much debate and evaluated in two small randomized studies．On the basis of these findings, the current guidelines have classified PVI as first-line therapy for PAF as a Class IIa recommendation．
Catheter-based PVI is most commonly performed with radiofrequency. Alternative energy sources have also been developed, including cryoballoon and balloon-based laser ablation. Surgical-based techniques such as the MAZE procedure are still being used and are often performed in conjunction with other cardiac surgical procedures.
In one small study, yoga training significantly reduced the number of symptomatic episodes, symptomatic non-AF episodes, and asymptomatic episodes．
Daily use of a rate controlling agent such as a beta blocker, calcium channel blocker, or digoxin is generally not needed in PAF. However, such drugs may be considered in patients with highly symptomatic episodes and can be used for an acute episode. Some patients are maintained on one of these drugs to control the ventricular rate when PAF occurs.
As a group, patients with paroxysmal atrial fibrillation (PAF) have a risk for embolic events that appears to be similar to that in patients with persistent AF, although the data are not conclusive．The approach to antithrombotic therapy in patients with PAF is felt by some experts to be similar to that in patients with persistent or permanent AF.