Radiofrequency ablation for atrial fibrillation

Radiofrequency catheter ablation effective treatment with paroxysmal atrial fibrillation.

Effective therapy in patients with recurrent episodes of arrhythmia despite anti arrhythmic drug therapy.

The procedure continues to improve in its efficacy and safety using intravascular ultrasound guidance of the transseptal puncture and electroanatomic mapping to guide the ablation.

Catheter based ablation for refractory paroxysmal atrial fibrillation is typically performed with the use of radiofrequency or cryo-thermal energy that heats or freezes tissue, respectively, to electrically isolate the pulmonary veins, which harbor triggers of atrial fibrillation.

An establish treatment for atrial fibrillation, particularly drug refractory paroxysmal AF.

Complications are not uncommon, with many patients having recurrent atrial fibrillation.

Procedurally involves pulmonary vein isolation, and and isolating ectopic beats that trigger AF paroxysms.

Atrial fibrillation catheter ablation complications include bleeding, pericardial complications, and stroke/TIA).

Indiscriminate thermal ablation, extending beyond the myocardium to adjacent tissues, has the potential of causing atrial esophageal fistula, hemidiaphragmatic paralysis, and pulmonary vein stenosis.

Fully 80% of procedures are done by clinicians who perform fewer than 25 AF ablations per year and in hospitals with fewer than 50 procedures per year.

The overall frequency of complications in a large study was 6.29% with cardiac complications 2.54%, vascular complications 1.53%, respiratory complications 1.3%, and neurological complications 1.02% (Deshmukh A et al),

For a patient with persistent AF, the results of pulmonary vein isolation are sub optimal and recurrent AF and atrial tachycardias often lead to repeat procedures.

In patients undergoing first time catheter ablation for persistent atrial fibrillation, the addition of pulmonary wall isolation to pulmonary vein isolation alone did not significantly improve freedom from atrial arrhythmia at 12 months compared with pulmonary vein isolation alone.

Mortality rate with AF catheter ablation 0.46%.

Experience level of less than 25 procedures, and hospital volume of less than 50 procedures significantly associated with adverse outcomes.

Costs averaged 15-$20,000.

Fibrosis and myolysis common in atria when AF becomes persistent.

Extensive atrial fibrosis detected by magnetic resonance imaging predicts a poor outcome after ablation.

In a random assignment of 294 patients with paroxysmal AF to antiarrhythmic drug therapy or radiofrquency catheter ablation as first line therapy: no significant difference between treatment groups in cumulative burden of AF over 2years(Nielsen JC et al).

In a multicenter study examining the incidence and predictors of asymptomatic AF after radiofrequency ablation, using continuous monitoring shows it significantly reduces the burden of AF, and the proportion of asymptomatic AF episodes increases (Verma A et al).

Success rates range from about 60% to 75%, compared with drug success from about 25% to 50%.

Contemporary estimates of success at one year after ablation, as defined by the absence of medications are 67 to 74% for paroxysmal atrial fibrillation and 43% for persistent and long-standing persistent atrial fibrillation.

For patients with symptoms, catheter ablation can improve quality-of-life to a greater extent than a drug therapy.

Catheter ablation has the added benefit of reducing AF burden and cardiovascular hospitalizations.

CABANA study explored the primary results on cardiovascular outcomes in mortality randomizing patients to receive catheter ablation or to receive drug therapy: the analysis revealed the patients did not experience a significant decrease or increase in the end point of death, disabling stroke, serious bleeding, or cardiac arrest.

More than 50% of patients treated with ablation have a recurrence of AF over four years, and some require a repeat ablation.

The incidence of major complications is 1% to 5%.

Atrioesophageal fistula is a serious complication.

Quality of life is better in patients receiving ablation compared with drugs.

It is unclear whether ablation reduces the risk for stroke or improves survival.

Symptomatic patients with paroxysmal AF after failure of one or more class 1 or 3 antiarrhythmics drugs can be considered for ablation.

Among patients with symptomatic AF despite the use of antiarrhythmic medications, there is an improvement in quality of life at 12 months in those treated with catheter ablation compared with those treated with anti-arrhythmic medication (Blomstrom-Lundqvist, C).

Ablation as a first-line for some patients with paroxysmal AF and no structural heart disease.

Indicated for treatment of patients with symptomatic AF in whom one or more attempts at class 1 or 3 antiarrhythmic drug therapy have failed.

Catheter ablation of AF has potentially life-threatening complications, such as an atrio-oesophageal fistula, stroke, and cardiac tamponade.

These major complications are rare and falling in incidence.

The vein of Marshall is an embryological remnant of the left superior vena cava and is implicated in the pathogenesis of AF.
It is felt to be a source of AF trigger and a tract for parasympathetic and sympathetic inner actions that modulate electrophysiological properties of atrial tissue and contribute to  AF maintenance.
The vein of Marshall is located within the mitral isthmus, critical for atrial tachycardia.
A balloon cannulation and ethanol infusion in the vein of Marshall can create a local ablation, eliminate AF triggers and vein of martial inner action, facilitate mitral isthmus ablation.
In a randomized trial of patients with persistent atrial fibrillation treatment with combined cathetervablation and vein of Marshall ethanol infusion had better outcomes compared with catheter ablation alone: freedom from AF or prolonged atrial tachycardia in 49% versus 38% and both six and 12 months.

Catheter ablation is superior to antiarrhythmic drugs in maintaining sinus rhythm improve the quality of life and patients in whom drugs have failed.


Catheter ablation as a first line treatment may be better than antiarrhythmic drugs in preventing the recurrence of atrial tachyarrhythmias, including the EF burden, and improving patient well-being.


Among patients receiving initial treatment for symptomatic, paroxysmal A F there was a significant lower rate of atrial fibrillation recurrence with catheter cryoballoon ablation than with antiarrhythmic drug therapy (Andrade JG).

Initial treatment of paroxysmal atrial fibrillation with catheter cryoablation is associated with a lower incidence of persistent atrial fibrillation or recurrent atrial tachyarrhythmias over three years (Andrade JG).

Among patients with atrial fibrillation and endstage heart failure, the combination of catheter ablation and medical therapy was associated with a lower likelihood of death from any cause, implantation of it left ventricular assist device or urgent  heart transplantation than medical therapy alone.

In a randomized trial cryoballoon ablation as the initial therapy for AF was superior to drug therapy for the prevention of atrial arrhythmia recurrence In patients with paroxysmal atrial fibrillation (Wazni, O).

Pulsed field ablation among patients with paroxysmal atrial fibrillation is non-inferior to conventional thermal ablation in regards to procedural failure, atrial tachyarrhythmias, antiarrhythmic, drug use, cardioversion, or repeat ablation or complications at one year (ADVENT Investigators).

Pulsed field ablation, uses high-voltage electrical fields on a microsecond scale that results in cellular membrane instability and electrophoresis resulting in cell death.

It is highly effective in eliminating electrical potentials, or arrhymogenic substrate with selectivity to the targeted myocardium without evidence of collateral injury to surrounding tissues.

Procedure time is much shorter with pulsed field, ablation than with thermal ablation.


Many patients continue to have episodes of atrial fibrillation after ablation, with some episodes causing no symptoms.


It is estimated that at least 50% of patients who undergo ablation will have a recurrence of atrial fibrillation by five years, and the recurrence confers a predisposition to a non-trivial risk of stroke and systemic embolism.


For patients undergoing ablation for AF, it is known that they should start anticoagulation therapy at least three weeks before the procedure and should be continued during the  procedure and for at least months two months afterward.

This findings suggest that anticoagulation should be continued after ablation in at risk patients.


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