For Long-standing Persistent AF , How About Empirical LAA Isolation ?
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American College of Cardiology Extended Learning
The ‘ Metastatic Cancer of Electrophysiology ’
For Long-standing Persistent AF , How About Empirical LAA Isolation ?
Longstanding persistent atrial fibrillation ( AF ) is the most challenging type of AF to treat with catheter ablation . During 5-year followup , Roland R . Tilz , MD , and colleagues noted that of 202 such patients treated with circumferential pulmonary vein isolation ( PVI ), single- and multiple ablation procedure success was 20 % and 45 %, respectively . 1 Compare that to the single procedure success rate seen in patients with paroxysmal AF ( 40 % at 1 year and 30 % at 5 years ) and for multiple procedures (> 80 % and > 60 % at 5 years ). 2 , 3
In an editorial accompanying the paper by Tilz et al ., longstanding persistent AF was referred to as ‘ the metastatic cancer of electrophysiology ’: It is one of the most difficult problems to treat and until recently , with no options , patients were expected to learn to live with their burden . 4 The authors of the commentary , all from St . David ’ s Medical Center , Austin , TX , wrote : “ At least two-thirds of the population improved after a long follow-up . This is not an inconsequential number and would be seen as a major victory in cancer medicine .”
Several studies have shown that , in addition to pulmonary vein ( PV ) isolation , other areas may be the source of initiation and maintenance of AF in patients . The most common non-PV sites are the superior vena cava , the ligament of Marshall , the coronary sinus , the crista terminalis , the left atrial posterior wall , and the left atrial appendage ( LAA ).
Luigi Di Biase , MD , PhD , is director of arrhythmia services , section head of electrophysiology , and associate professor of medicine ( cardiology ) at Einstein / Montefiore in New York City , NY . Di Biase and colleagues think that the latter is an under-recognized trigger site of AF . In one study of nearly 4,000 patients , they reported that LAA appears to be responsible for arrhythmias in 27 % of patients presenting for repeat procedures . 5 They concluded that isolation of the LAA “ could achieve freedom from atrial fibrillation in patients presenting for a repeat procedure when arrhythmias initiating from this structure are demonstrated .”
EMPIRICAL LAA ISOLATION Di Biase and colleagues recently reported their results treating patients with longstanding persistent AF using empirical electrical isolation of the LAA plus extensive PV antrum and non-PV trigger ablation ( n = 85 ; group 1 ) versus extensive ablation alone ( n = 88 ; group 2 ) in a multicenter randomized trial . ( The effects of LAA isolation in addition to PV isolation has not been investigated before in a prospective randomized fashion .)
Empirical isolation of the LAA improved the long-term freedom from AF without increasing complications . Specifically , at 12-month follow-up , freedom from recurrence after a single procedure
( and without anti-arrhythmic drug therapy ) was seen in 48 ( 56 %) of the patients with empirical LAA isolation vs . 25 ( 28 %) in the ablation-only group ( p = 0.001 ). In group 2 , about one-third of patients showed firing from LAA during isoproterenol testing but a sustained arrhythmia was observed in only eight of these patients and LAA was isolated in these patients .
“ [ The results ] are interesting and important , as they add new information about the potential role of LAA triggers in patients with longstanding persistent atrial fibrillation .”
– Gerhard Hindricks , MD
Sixty-two patients ( 27 group 1 ; 35 group 2 ) underwent a second procedure and LAA isolation was performed in all of these patients undergoing repeat ablation . After an average of 1.3 procedures , success at 24-month follow-up was 65 ( 76 %) in group 1 and 49 ( 56 %) in group 2 ( p = 0.003 ).
After adjusting for age , sex , and left atrial diameter , LAA isolation plus standard ablation was associated with a 55 % reduction in overall recurrence ( HR : 0.45 ; p = 0.004 ).
The mean radiofrequency time was significantly longer with empirical LAA isolation ( 93.1 ± 26.2 minutes versus 77.4 ± 29.9 minutes ; p < 0.001 ). But there were no significant differences in safety endpoints when LAA was empirically added to extensive ablation .
At ESC 2015 , where the data were presented , the discussant for the trial was Professor Gerhard Hindricks , MD , director of the department of electrophysiology at Leipzig University Heart Center , Germany . The results , he said , “ are interesting and important , as they add new information about the potential role of LAA triggers in patients with longstanding persistent atrial fibrillation .” However , overall he considers the trial hypothesis generating rather than fully
To listen the interview with Luigi Di Biase , MD , Phd , visit the CSWN YouTube channel or scan the QR code . Interview conducted by S . Ben Freedman , MBBS .
conclusive . Further studies are necessary , he said , before LAA isolation can be recommended as an integral part of catheter ablation of longstanding persistent AF . ■
REFERENCES :
1 . Tilz R , Rillig A , Thum A , et al . J Am Coll Cardiol . 2012 ; 60:1921-9 .
2 . Weerasooriya R , Khairy P , Litalien J . J Am Coll Cardiol . 2011 ; 57:160-6 .
3 . Medi C , Sparks PB , Morton JB , et al . J Cardiovasc Electrophysiol . 2011 ; 22:137-41 .
4 . Burkhardt J , Di Biase L , Natale A . J Am Coll Cardiol . 2012 ; 60:1930-32 .
5 . Di Biase L , Burkhardt JD , Mohanty P , et al . Circulation . 2010 ; 122:109-18 .
Take-aways
• Catheter ablation of longstanding persistent AF is a complex procedure with higher recurrence rates compared with catheter ablation of paroxysmal AF .
• Investigators conducted an RCT to determine whether empirical left atrial appendage ( LAA ) isolation along with the standard approach of pulmonary vein isolation and ablation of extrapulmonary triggers is superior to the standard approach alone .
• In patients with longstanding persistent AF , the empirical isolation of the LAA improves longterm freedom from atrial arrhythmias without increasing complications .
20 CardioSource WorldNews : Interventions May / June 2016