Contribution This systematic review found that radiofrequency ablation after a failed drug course maintained sinus rhythm more often than continuation of drug therapy alone .
The benefits of maintaining sinus rhythm with antiarrhythmic drugs appeared to be offset by the serious adverse effects of the drugs .
Context Is radiofrequency catheter ablation a better alternative than medical therapy for patients with atrial fibrillation ?
The Editors Atrial fibrillation is the most common sustained arrhythmia in clinical practice ( 1 ) .
Its prevalence increases with age , from 0.1 % in people younger than 55 years to more than 9 % by 80 years of age ( 2 ) .
The heavy burden of atrial fibrillation on morbidity , mortality , and health care re sources creates a pressing need for novel approaches to management .
In some patients , adequate pharmacologic slowing of the ventricular response rate ( a rate-control strategy ) is sufficient to control symptoms .
However , many patients remain symptomatic from the lack of organized atrial contraction and the persistent irregularity of the ventricular response in atrial fibrillation .
In such patients , the appropriate treatment is restoration of normal sinus rhythm , achieved electrically or chemically ( a rhythm-control strategy ) ( 2 ) .
Radiofrequency catheter ablation is a promising approach that offers the benefits of maintaining sinus rhythm without the adverse effects of antiarrhythmic drugs .
Catheter ablation for atrial fibrillation is based on the underst and ing that electrical activity emanating from the pulmonary veins frequently serves as a trigger for atrial fibrillation .
In the late 1990s , Hassaguerre and colleagues ( 5 ) observed that elimination of local electrograms at these foci with radiofrequency energy reduced the risk for recurrence of atrial fibrillation .
Currently , the foundation of most atrial fibrillation ablation procedures is to target and electrically isolate the pulmonary veins ( 6 ) .
This may be achieved by delivering lesions immediately outside the ostia of the pulmonary veins or along a wider area in the left atrium encircling the veins .
Additional lesion sets have been used to ablate nonpulmonary vein triggers of atrial fibrillation and to target atrial areas thought to be responsible for maintaining atrial fibrillation ( 6 ) .
These linear lesions may be created in the posterior left atrium , the roof of the left atrium , the interatrial septum , and the isthmus formed between the mitral annulus and the pulmonary vein or left atrial appendage .
At present , the Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation , put forth by the Heart Rhythm Society and endorsed by several professional organizations , states that the foundation of most atrial fibrillation ablation procedures is to target the pulmonary veins , pulmonary vein antra , or both ( 6 ) .
The panel advised us that 8-mmtip and irrigated-tip catheters are now the catheters of choice for radiofrequency ablation of atrial fibrillation in the United States .
The conventional 4-mmtip catheter is rapidly being phased out of use for this indication .
The following 3 key questions were formulated : 1 .
What is the effect of radiofrequency catheter ablation on short-term ( 6 to 12 months ) and long-term ( > 12 months ) rhythm control ; rates of congestive heart failure ; changes in the size of the left atrium and ventricle ; rates of stroke ; quality of life ; avoiding anticoagulation ; and readmissions for paroxysmal , persistent , and long-st and ing persistent ( chronic ) atrial fibrillation ?
2 .
How does the effect of radiofrequency ablation  on rhythm control differ among the various techniques used ?
3 .
What are the short- and long-term complications and harms associated with radiofrequency ablation ?
Transcranial Doppler detection of microembolic signals during pulmonary vein antrum isolation: implications for titration of radiofrequency energy.
BACKGROUND Cerebrovascular events are an important complication during pulmonary vein antrum isolation ( PVAI ) .  Microembolic signals ( MES ) have been associated with stroke and neurological impairment . However , the incidence of MES during PVAI , and their relationship to microbubble formation and radiofrequency ( RF ) parameters are unknown . OBJECTIVES We sought to assess the relationship between MES , microbubble detection , and neurological outcome and the impact of RF titration strategy on these parameters . METHODS We studied 202 patients in two groups undergoing PVAI using an intracardiac echocardiography (ICE)-guided technique .  MES were detected by transcranial Doppler ( TCD ) using insonation of the middle cerebral arteries . The number of microbubbles on ICE were qualitatively labeled as FEW , MODERATE , and SHOWER . In group I ( n = 107 ) , RF output was titrated to avoid microbubble formation and in group II ( n = 95 ) , st and ard power-limited RF output was used . RESULTS TCD detected MES in all 202 patients during PVAI with an average of 1,793 + /- 547 per patient ; 90 % were detected during left atrial ablation . Over 85 % of MES occurred after microbubbles . Group I patients had significantly lower numbers of MES ( 1,015 + /- 438 per patient ) compared to group II patients ( 2,250 + /- 864 per patient ) ( P < 0.05 ) . Group II also had a 3.1 % incidence of acute neurological complications versus 0.9 % in group I ( P = 0.10 ) . Patients with clinical events had significantly higher numbers of MES . There were no significant correlations between RF power , temperature , or impedence and MES number . CONCLUSIONS MES directly correlate to the amount of microbubble formation on ICE , and may result in cerebroembolic complications . Titration of RF according to microbubble formation by ICE during PVAI may be important for minimizing the occurrence of MES and possibly acute neurological complications
Contribution This systematic review found that radiofrequency ablation after a failed drug course maintained sinus rhythm more often than continuation of drug therapy alone .
The benefits of maintaining sinus rhythm with antiarrhythmic drugs appeared to be offset by the serious adverse effects of the drugs .
Context Is radiofrequency catheter ablation a better alternative than medical therapy for patients with atrial fibrillation ?
The Editors Atrial fibrillation is the most common sustained arrhythmia in clinical practice ( 1 ) .
Its prevalence increases with age , from 0.1 % in people younger than 55 years to more than 9 % by 80 years of age ( 2 ) .
The heavy burden of atrial fibrillation on morbidity , mortality , and health care re sources creates a pressing need for novel approaches to management .
In some patients , adequate pharmacologic slowing of the ventricular response rate ( a rate-control strategy ) is sufficient to control symptoms .
However , many patients remain symptomatic from the lack of organized atrial contraction and the persistent irregularity of the ventricular response in atrial fibrillation .
In such patients , the appropriate treatment is restoration of normal sinus rhythm , achieved electrically or chemically ( a rhythm-control strategy ) ( 2 ) .
Radiofrequency catheter ablation is a promising approach that offers the benefits of maintaining sinus rhythm without the adverse effects of antiarrhythmic drugs .
Catheter ablation for atrial fibrillation is based on the underst and ing that electrical activity emanating from the pulmonary veins frequently serves as a trigger for atrial fibrillation .
In the late 1990s , Hassaguerre and colleagues ( 5 ) observed that elimination of local electrograms at these foci with radiofrequency energy reduced the risk for recurrence of atrial fibrillation .
Currently , the foundation of most atrial fibrillation ablation procedures is to target and electrically isolate the pulmonary veins ( 6 ) .
This may be achieved by delivering lesions immediately outside the ostia of the pulmonary veins or along a wider area in the left atrium encircling the veins .
Additional lesion sets have been used to ablate nonpulmonary vein triggers of atrial fibrillation and to target atrial areas thought to be responsible for maintaining atrial fibrillation ( 6 ) .
These linear lesions may be created in the posterior left atrium , the roof of the left atrium , the interatrial septum , and the isthmus formed between the mitral annulus and the pulmonary vein or left atrial appendage .
At present , the Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation , put forth by the Heart Rhythm Society and endorsed by several professional organizations , states that the foundation of most atrial fibrillation ablation procedures is to target the pulmonary veins , pulmonary vein antra , or both ( 6 ) .
The panel advised us that 8-mmtip and irrigated-tip catheters are now the catheters of choice for radiofrequency ablation of atrial fibrillation in the United States .
The conventional 4-mmtip catheter is rapidly being phased out of use for this indication .
The following 3 key questions were formulated : 1 .
What is the effect of radiofrequency catheter ablation on short-term ( 6 to 12 months ) and long-term ( > 12 months ) rhythm control ; rates of congestive heart failure ; changes in the size of the left atrium and ventricle ; rates of stroke ; quality of life ; avoiding anticoagulation ; and readmissions for paroxysmal , persistent , and long-st and ing persistent ( chronic ) atrial fibrillation ?
2 .
How does the effect of radiofrequency ablation  on rhythm control differ among the various techniques used ?
3 .
What are the short- and long-term complications and harms associated with radiofrequency ablation ?