Optimal approach to the ablation of PAF: Importance of identifying triggers David J. Callans, MD University of Pennsylvania School of Medicine AF ablation Penn experience Antral (circumferential) PV ablation Ablation guided by -- Multipolar circular catheter recording -- three dimensional mapping -- intracardiac echocardiography PV triggers provoked (pre/post) and non-pv triggers mapped; importance of high dose isoproterenol Not built for speed but safety and to study what subsequent approaches may be helpful Substrate ablation: potential mechanism(s) 1. reduction in functional atrial size 2. pulmonary vein isolation or change in conduction of triggers (? affecting ability to induce AF) 3. elimination of anchor points for rotors in the posterior venous atrium 4. ablation of the ligament of Marshall 5. autonomic denervation Haissaguerre M: NEJM 1998 Pappone C: Circulation 2001 1
Substrate ablation vs. PV isolation Freedom from symptomatic PAF off AAD: 89 vs 67% Oral H: Circulation 2003 Identification of PV ostia with ICE LSPV LIPV 2
Provoking triggers for AF initiation Stimulation to exclude accessory pathway/ AVNRT Initiation of triggers in patients with infrequent / absent spontaneous triggers - 93% of patients Isoproterenol (6-20mcg/min dose guided by trigger onset/side effects most tolerate average 12 mcg/min) triggers provoked in 79% A fib initiation with rapid pacing during low dose isoproterenol (1-3ug) infusion followed by CV triggers provoked in additional 14% Even more important as test of cure post RF Non pulmonary vein triggers of AF AVNRT 16 Left atrial posterior wall 11 Crista Terminalis 9 Eustacian Ridge/ CS Os region Mitral Valve Annulus 5 Superior Vena Cava 4 Fossa Ovalis/Limbus 4 Para-Hisian 3 Right Atrial Appendage 3 Tricuspid Valve Annulus 2 Ligament of Marshall 1 8 Sinus I avf V1 Lasso1 LA tachycardia from medial mitral annulus triggering RSPV AF trigger Lasso 10 Abld Ablp CSd CSp CRd SVC trigger CRp 3
AF caused by AVNRT (diagnosed in lab) Influence of AF type on Non PV triggers I V1 Total 761 pts Paroxysmal 440 pts (58%) Persistent 282 pts (37%) Persist > 1 yr 39 pts (5%) HBEp HBEd CS p CS d CT d AF Observed in 4.3% (new diagnosis) 13/27, AVNRT was the only trigger 12/13 no AF after slow pathway modification alone Any Non PV trigger 113 pts (15%) 72 (16%) 39 (14%) 2(6%) AT 89pts (12%) 53 (12%) 35 ( 12%) 1 ( 3%) CT p RVA AVNRT or AVRT 28 pts (4%) 21 (5%) 6 (2%) 1 (3%) Acute PV reconnection 30 minutes after isolation 153/290 pts (52.8%) and 231/856 PVs (27.0%) Baseline Lasso in LSPV AF Initiation Immediate post RF LIPV Predictors of acute PV reconnection LSPV RIPV RSPV LA size persistent AF HTN sleep apnea age Reconnection after 20 min LSPV re-isolated 0 10 20 30 40 % Acute Reconnection Sauer et al Heart Rhythm 2006 4
RSPV isolated RSPV isolated 90 min Failure of PVI = reconnected PV Isoproterenol RSPV reisolated 74 patients (11 F, mean age 56) One or more segments reconnected in 1 previously ablated PV 97% Triggers from previously ablated PV: 77% Triggers from previously non-ablated PV: 15% Non-PV triggers 18% Left atrial flutter 5% Repeat PVI resulted in AF control in 86% Type of AF (paroxysmal / permanent) not a factor Callans DJ: JCE 2004 Advantages to less extensive ablation Less ablation likely to decrease risk of PV stenosis, collateral damage, thromboembolic complications Physiology of AF initiation is clear, AF maintenance is not Ablation lesions confined to PV LA junction may preserve posterior LA function (mechanical, endocrine) Lemola K: Heart Rhythm 2005 Verma A: JCE 2006 Macro-reentrant left atrial flutter rarely observed post PVI -- proarrhythmic effect of incomplete LA lines Jais P: Circulation 2004 Sanders P: Heart Rhythm 2004 5
LA flutter after wide area circumferential ablation Pappone, Circulation 2004: 10% Chugh/Morady, Heart Rhythm 2005: 24% Karch/Schmitt, Circulation 2005: 18% (cf. 2% with PV isolation) Haissaguerre M: JCE 2005 Takahashi Y: JACC 2007 mitral annular corridor focal Mesas, JACC 2004 Advantages to substrate ablation May be simpler to perform: single transseptal, shorter procedure duration, less fluoroscopy May addresses other possible mechanisms in addition to initiation of AF by PV triggers Effect of ablation? not as susceptible to Achilles heal of PV isolation: reconnection May be more effective in established AF Reporting Outcome LACA vs SOA F/U = 6 mos Repeat Procedures 0% 33% Blanking Period Number on Drugs Monitoring Techniques Number of Repeat Procedures LACA vs CONTROL F/U = 12 mos Oral H et al: Circulation 2003 Oral H et al: NEJM 2006 % of patients without AF PV Antral Isolation and Non PV triggers 100 80 60 40 20 0 20± 9 months (6-60 months) N = 366pts Gentlesk et al: JCE 2006 28% 6
Penn Experience - PV Isolation plus elimination of non PV triggers (902 pts, > 1 year follow up) 100 80 60 40 20 0 87% 10% 12% 65% 90% 9% 11% 70% 81% 12% 13% 56% Overall PAF Persist/Perm 30 +/- 18 mos 30 +/- 19 mos 28 +/- 16 mos (Range 12-97 mos) (Range 12-97 mos) (Range 12-97 mos) N=902 N=604 N=298 AF Control on Restarted AAD AF Control on AAD-never stopped No AF off AAD Repeat Procedure: 23%=PAF, 31% Persistent (26% > 1 yr) PVI + trigger ablation for paroxysmal AF My opinions -- 1. PV isolation is a necessary part of any ablation strategy 2. The effect of extensive ablation on LA function is not completely clear, but is probably not beneficial 3. Recurrent AF after ablation is virtually always due to PV reconnection 4. Non PV triggers can cause AF. Failure to consider them probably means failure 7