AF ABLATION Concepts and Techniques Antony F Chu, M.D. Director of Complex Ablation Arrhythmia Services Section Division of Cardiology at the Rhode Island and Miriam Hospital
HIGHLIGHTS The main indications for AF ablation: failure of drug therapy inability to tolerate drug therapy quality of life AF ablation objective: to create scar tissue in rings around the ostia of the pulmonary veins in the left atrium to electrically isolate TRIGGERS of fibrillation and areas that sustain AF
HIGHLIGHTS Results of the ablation are superior to those of drug therapy Success rates of ablation are generally higher for those with paroxysmal atrial fibrillation than for those with persistent atrial fibrillation (overall >70%) More patients with atrial fibrillation are asking their physicians about catheter-based radiofrequency ablation as a treatment option
AF ABLATION:WHAT IT S NOT AFIB is NOT the same determining the clinical context of a patient s AF is key to creating viable therapeutic strategy Pulmonary Vein Isolation is not a cure but valuable in managing AF burden Patients must understand that ablation therapy will NOT eliminate the need to take anticoagulant drugs
AFIB BURDEN 2-3 million Americans have AF 70% of AF patients are between the ages of 65 and 85 The number of Americans with atrial fibrillation is expected to double by 2050
AFIB INCREASED MORTALITY Framingham Heart Study, AF was associated with a 1.5- to 1.9-fold mortality risk after adjustment for the preexisting cardiovascular conditions with which AF was related. The decreased survival seen in men and women and across a wide range of ages
The Need For A True AF Solution AF Population is Expected to Increase Substantially Projected U.S. AF Population (millions) Miyasaka Y, et al. Secular trends in incidence of atrial fibrillation in Olmsted county, Minnesota, 1980 to 2000, and implications on the projections for future prevalence. Circulation. 2006;114:119-125.
RHYTHM VS RATE Several randomized clinical trials (most importantly AFFIRM) found that attempting to restore and maintain sinus rhythm with anti-arrhythmic drugs has no significant survival benefit compared with a strategy of controlling the heart rate only Recent studies, including an AFFIRM investigator analysis, suggest that rhythm control may have a survival benefit over rate control if sinus rhythm achieved without the adverse effects of antiarrhythmic drugs
RHYTHM VS RATE Is the benefit of sinus rhythm eliminated by the toxicity of anti-arrhythmic therapy?
What are the Symptoms of AF? 60-90% of AF Patients are Symptomatic
LONE AF
STRUCTURAL HD & AF
Treatment for Paroxysmal, Lone AF is in View Paroxysmal, Lone AF AF Population 12% are Paroxysmal 1 12% have Lone AF 2 1 Atrial Fibrillation Investigators. Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation. Arch Intern Med 1994;154:1449-1457. 2 Fuster and Rydén et al. ACC/AHA/ESC Practice Guidelines. JACC Vol. 38, No. 4, October, 2001.
However, New Techniques are Needed to Address Persistent & Permanent AF Paroxysmal, Lone AF Paroxysmal w SHD or Enlarged LA Persistent AF Longstanding/ Permanent AF AF Population 88% are Persistent or Permanent 1 88% have Structural Heart Disease 2 85% 60 yrs old 2 1 Atrial Fibrillation Investigators. Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation. Arch Intern Med 1994;154:1449-1457. 2 Fuster and Rydén et al. ACC/AHA/ESC Practice Guidelines. JACC Vol. 38, No. 4, October, 2001.
Lone AF May Be Benign; AF with LA Size or SHD is NOT Increased LA size is highly predictive of AF, stroke, and mortality 1 Lone AF population progressed into two distinct groups: 1 Pts with normal LA size experienced a benign clinical course. Pts with enlarged atria experienced adverse events. No LA Size = No Complications LA Size = Complications 1 Osranek M. Left atrial volume predicts cardiovascular events in patients originally diagnosed with lone atrial fibrillation: three-decade follow-up. European Heart Journal (2005) 26, 2556 2561.
Left Atrial Size is a Predictor of AF Incidence Increase in Left Atrial Size Leads to AF As LA Size increases, 30% of patients develop AF in 10 years If LA Size does not increase, 10% of patients develop AF in 10 years Ommen SR, et al. Usefulness of serial echocardiographic parameters for predicting the subsequent occurrence of atrial fibrillation. Am J Card. Vol 87. June 1, 2001.
Relationship between AF w/ SHD & Heart Failure AF with SHD Must be Treated to Break the Cycle Atrial Fibrillation LV Dysfunction Left Atrial Size Progression of Structural Heart Disease Heart Failure Atrial Dysfunction Ommen SR, et al. Usefulness of serial echocardiographic parameters for predicting the subsequent occurrence of atrial fibrillation. Am J Card. Vol 87. June 1, 2001.
Atrial Fibrillation Caused by Atrial Remodeling Underlying Factors: Electrical, Contractile & Structural Electrical Remodeling AF Begets AF Atrial Fibrillation SHD Structural Remodeling Fibrosis Myolysis Glycogen Accumulation Cell Enlargement Cell Death SHD Contractile Remodeling
AF TRIGGER SITES Haissaguerre M et al. N Engl J Med 1998;339:659-666
Physiologic basis for AF ablation: ~80-90% of APDs triggering AF originate from pulmonary veins Four ECG leads Firing without exit to atrium Firing with exit to atrium Circular Mapping Catheter in RSPV Firing with exit to atrium triggering atrial fibrillation Ablation Catheter in LSPV Circular Mapping Catheter in RSPV Ablation Catheter in LSPV Coronary Sinus Catheter Right Atrial Catheter Right Atrial Catheter Coronary Sinus Catheter
AF IS NOT THE SAME
Structure and mechanism of AF
Common Lesions Performed in AF Ablation A. Circumferential ablation around left and right PV antra B. and C. Additional linear lesion sets for the roof, mitral isthmus, carinae, SVC, and cavotricuspid isthmus D. Targeting fractionated electrograms and/or ganglionic plexi LSPV LIPV LSPV LIPV SVC A. B. RSPV LSPV RIPV LIPV IVC SVC C. D. RSPV LSPV RIPV LIPV IVC SVC RSPV RIPV IVC SVC RSPV RIPV IVC PV = pulmonary vein; SVC = superior vena cava; LSPV = left superior pulmonary vein; RSPV = right superior pulmonary artery; LIPV = left inferior pulmonary vein; RIPV = right inferior pulmonary vein; IVC = inferior vena cava. Calkins H, et al. Heart Rhythm. 2007;4(6):816-861.
ABLATION ENERGY SOURCES RF- Radiofrequency Cryoablation Microwave Ultrasound- Hi frequency Laser
A Convergent Procedure Lesion Pattern Illustration of generic lesion set. Physician medical practice to modify as required. Epicardial Lesion Endocardial Lesion
N-Contact Device
Convergence of EPs & Surgeons Multidisciplinary Collaboration for a Single Procedure Surgeons Able to See Anatomy Visualize Lesion Connections Access Epicardial Substrates Create Linear Lesions Total Multidisciplinary Treatment Electrophysiologists Eliminate Surgeon Need for Chest Incisions Eliminate Need to Dissect Pericardial Reflections Able to Map Epicardial Lesions Confirm Conduction Block & PVI Confirm Inability to Induce Arrhythmias
Components of the Convergent Procedure Combining Strengths of EPs & Surgeons Together
Paracardioscopic Access Transdiaphragmatic Approach to Posterior Atria
Accessing Posterior Left Atrium Creating Lesions with Direct Visualization
Access Anterior LPV & Ligament of Marshall
Access Anterior RPV & Right Atrium
Percutaneous Endocardial Ablation Access Percutaneous Access Breakthrough Locations @ Pericardial Reflections
Endocardial Ablation Catheter and Lesion Locations Mapping Identifies Breakthrough @ Reflections Ablating RSPV @ Reflections Ablating RIPV @ Reflections Ablating LSPV @ Reflections
Ensures Isolation of the Posterior LA & PVs Activation Map Pre Lesion Creation Activation Map Post Lesion Creation
Post Epicardial Ablation Voltage Map Isolated RSPV Isolated RSPV & LIPV Isolated LIPV
Post Convergent Procedure Isolation of Posterior LA
Convergent Procedure Access No Chest Incisions, No Rib Spreading, No Lung Deflation, No Anterior Pericardial Incisions, No Dissections Access for Bilateral Thoracotomy Clamping Hybrid Procedure* Closed Chest Convergent Procedure Abdominal Access *Source: Medtronic, Inc. Minimally Invasive Vertical Approach for the Surgical Treatment of Lone Atrial Fibrillation.
Convergent Procedure Access Less Invasive Access, Smaller Incisions, Less Trauma Bilateral Thoracotomy Clamping Hybrid Procedure Chest Incisions After 3 Months Closed Chest Convergent Procedure Abdominal Access Site After 3 Months Bilateral Thoracotomy Chest Incisions Closed Chest Convergent Access
Procedure Mapping Comprehensive Biatrial Pattern with Post PVI Clamping Procedure No Posterior Lesions Posterior Lesions Post Convergent Procedure Isolated Posterior Activity Throughout Posterior Left Atrium Posterior Left Atrium is Isolated Kron J, et al. Management of recurrent atrial arrhythmias after minimally invasive surgical pulmonary vein isolation and ganglionic plexi ablation for atrial fibrillation. Heart Rhythm. 2010;7:445-451.
Protocol If in AF, cardiovert and look for ERAF Start isoproterenol 3, 6, 12, 20 mcg/min with titration every 3 minutes to look for APDs triggering AF Burst pace from LA (distal CS) from 250 to 180 msec If no triggers, then induce AF with rapid burst pacing with and without low dose ISO (2-3 mcg/min) and cardiovert again Perform PVI (proximal/antral isolation) with entrance AND exit block as endpoint Target any non-pv triggers that cause AF
Acute Endpoints for PAF Ablation - Recommendations PV isolation with entrance and exit block Persistent PV isolation confirmed at 20 + minutes In response to provocative maneuvers (Iso to 20mcg/Afib induction and CV with Iso) No PV reconnection and no PV APDs Target all Non PV triggers causing Afib SVC isolation only if AF trigger ( 3 %) Flutter line only if clinically observed flutter (9 %) 1% late CT Isthmus dependent flutter If make lines make sure there is block