Catheter Ablation Therapy for Persistent Atrial Fibrillation (CLEAR-AF)

Catheter Ablation Therapy for Persistent Atrial Fibrillation: Value of Additional Linear Ablation on Left Atrial Anterior Wall

Beijing Hospital, First Affiliated Hospital, Sun Yat-Sen University, Tianjin Medical University General Hospital, Wuhan Asia Heart Hospital, First Affiliated Hospital of Kunming Medical University

Use of catheter ablation for persistent atrial fibrillation (PerAF) remains controversial due to unsatisfactory long-term success rates (15% - 28.4%). The investigators' previous study indicated that the upper area of the left atrium (LA) plays an important role in PerAF, with the LA roof and mitral isthmus appearing to serve as main substrate in progression from PAF to PerAF and maintenance of fibrillatory activities. The investigators therefore hypothesized that AF should not be initiated or sustained if the latter crucial regions for AF maintenance are abolished. This study aimed to describe the efficacy and safety of additional linear ablation on the left atrial anterior wall for PerAF.

Although studies and guidelines have helped establish catheter ablation as preferred treatment for patients suffering from paroxysmal atrial fibrillation (PAF), use of catheter ablation for persistent atrial fibrillation (PerAF) remains controversial due to unsatisfactory long-term success rates (15% - 28.4%). The investigators' study indicated that the upper area of the left atrium (LA) plays an important role in PerAF, with the LA roof and mitral isthmus appearing to serve as main substrate in progression from PAF to PerAF and maintenance of fibrillatory activities. The investigators therefore hypothesized that AF should not be initiated or sustained if the latter crucial regions for AF maintenance are abolished. This was confirmed using a stepwise pure linear ablation protocol, consisting of a line across the LA roof and extending along the anterior wall of pulmonary veins (PV) antrum to mitral valve annulus (MVA) without PV isolation; the approach appeared safe and effective with long-term (5.2 years) follow-up success rate of 40% for PerAF. This study will evaluate efficacy and safety of circumferential pulmonary vein isolation (CPVI) + LA roof linear ablation + LA anterior wall (LAAW) linear ablation combined with high density mapping and contact force sensing techniques for perAF. This study is expected to provide a practical and guided catheter ablation strategy with maximized safety and efficacy through use of contact force sensing technique, which will be accepted by other qualified electrophysiology laboratories.

Patients who undergo CPVI+LA roof linear ablation+/ MI linear ablation, and additional LAAW linear ablation using ThermoCool SmartTouch catheter.

Patients who undergo CPVI+LA roof +/ MI linear ablation using ThermoCool SmartTouch catheter, without LAAW linear ablation.

Freedom from AF at 1 year without any anti-arrhythmic drugs. Recurrent AF is defined as documented AF (through 12-lead ECG or Holter) period lasting >30 seconds after a 3-month blanking period.

From August, 2016 to July 2019. The overall Time Frame for AF recurrence is being assessed up to 36 months.

From August, 2016 to July 2017. The overall Time Frame for AF termination during ablation procedure is being assessed up to 12 months.

From August, 2016 to July 2017. The overall Time Frame for frequency of complications is being assessed up to 12 months.

From August, 2016 to July 2017. The overall Time Frame for average radiation exposure is being assessed up to 12 months.

From August, 2016 to July 2019. The overall Time Frame for frequency of redo procedures is being assessed up to 12 months.

From August, 2016 to July 2017. The overall Time Frame for average ablation time and procedure time are being assessed up to 12 months.

Inclusion Criteria: - The main inclusion criterion is patients suffering from drug refractory persistent atrial fibrillation and referred to catheter ablation therapy. Persistent AF is defined as continuous AF for over 7 days, or lasting no more than 7 days but requiring pharmacological or electrical cardioversion. Exclusion Criteria: Patients without spontaneous ongoing AF at the beginning of the procedure; Age: <18 years or >70 years; LA size > 55mm measured on echocardiogram; Previous AF ablation history including surgical ablation; Documented LA thrombus; Severe pulmonary diseases; Previous cardiac surgical history.

January CT, Wann LS, Alpert JS, Calkins H, Cigarroa JE, Cleveland JC Jr, Conti JB, Ellinor PT, Ezekowitz MD, Field ME, Murray KT, Sacco RL, Stevenson WG, Tchou PJ, Tracy CM, Yancy CW; ACC/AHA Task Force Members. 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014 Dec 2;130(23):2071-104. doi: 10.1161/CIR.0000000000000040. Epub 2014 Mar 28. No abstract available. Erratum In: Circulation. 2014 Dec 2;130(23):e270-1.

Camm AJ, Lip GY, De Caterina R, Savelieva I, Atar D, Hohnloser SH, Hindricks G, Kirchhof P; ESC Committee for Practice Guidelines (CPG). 2012 focused update of the ESC Guidelines for the management of atrial fibrillation: an update of the 2010 ESC Guidelines for the management of atrial fibrillation. Developed with the special contribution of the European Heart Rhythm Association. Eur Heart J. 2012 Nov;33(21):2719-47. doi: 10.1093/eurheartj/ehs253. Epub 2012 Aug 24. No abstract available. Erratum In: Eur Heart J. 2013 Mar;34(10):790. Eur Heart J. 2013 Sep;34(36):2850-1.

Chao TF, Tsao HM, Lin YJ, Tsai CF, Lin WS, Chang SL, Lo LW, Hu YF, Tuan TC, Suenari K, Li CH, Hartono B, Chang HY, Ambrose K, Wu TJ, Chen SA. Clinical outcome of catheter ablation in patients with nonparoxysmal atrial fibrillation: results of 3-year follow-up. Circ Arrhythm Electrophysiol. 2012 Jun 1;5(3):514-20. doi: 10.1161/CIRCEP.111.968032. Epub 2012 May 1.

Tilz RR, Rillig A, Thum AM, Arya A, Wohlmuth P, Metzner A, Mathew S, Yoshiga Y, Wissner E, Kuck KH, Ouyang F. Catheter ablation of long-standing persistent atrial fibrillation: 5-year outcomes of the Hamburg Sequential Ablation Strategy. J Am Coll Cardiol. 2012 Nov 6;60(19):1921-9. doi: 10.1016/j.jacc.2012.04.060. Epub 2012 Oct 10.

Sorgente A, Tung P, Wylie J, Josephson ME. Six year follow-up after catheter ablation of atrial fibrillation: a palliation more than a true cure. Am J Cardiol. 2012 Apr 15;109(8):1179-86. doi: 10.1016/j.amjcard.2011.11.058. Epub 2012 Jan 14.

Yao Y, Zheng L, Zhang S, He DS, Zhang K, Tang M, Chen K, Pu J, Wang F, Chen X. Stepwise linear approach to catheter ablation of atrial fibrillation. Heart Rhythm. 2007 Dec;4(12):1497-504. doi: 10.1016/j.hrthm.2007.07.028. Epub 2007 Aug 11.

Wu L, Yao Y, Zheng L, Zhang K, Zhang S. Long-term follow-up of pure linear ablation for persistent atrial fibrillation without circumferential pulmonary vein isolation. J Cardiovasc Electrophysiol. 2014 May;25(5):471-476. doi: 10.1111/jce.12360. Epub 2014 Jan 24.