Convergent Ablation: Theory and TechniquesKevin J. Makati, MD, FACC, FHRSDirector Arrhythmia DepartmentSt. Joseph’s HospitalChairman, Rhythm SectionBaycare Health Systems
Andrew J. Sherman, MDChief, Department of Cardiothoracic SurgerySt. Joseph’s HospitalChairman, Cardiac SurgeryBayCare Health System
Disclosures• Atricure Surgical• Boston Scientific• Medtronic• Abbott
Baycare Health Systems• Nonprofit health care system spanning 15 hospitals, 7
Urgent Care centers, 3100 physicians, 544,678 ER visits• Cardiosurgical procedures including TAVR, MitralClip,
Atricure Ablation/Atriclip, LVAD*• Arrhythmia services including Adult/Pediatric EP,
fluoroless ablation, Adult/Ped device management including extraction, venoplasty, His Bundle pacing, AF solutions, VA management including epicardial and hemodynamic assisted.
• Multidisciplinary approach to cardiac disease
Premise• Hybrid approaches are increasingly utilized as a
primary AF ablation strategy.• Recruitment of both surgeon and electrophysiologist
may improve overall procedural outcome• The posterior left atrial wall is now well established
as an important ablation target.• The Convergent ablation performed as a single
procedure provides immediate lesion set adjudication and comprehensive substrate elimination using a minimally invasive technique.
•The mechanism of persistent AF remains controversial.•Interaction between initiating triggers and remodeled substrate
Multiple WaveletsClassical paradigm•Moe et al 1964•Konings et al 1994•Cox et al 1991•DeGroot et al 2010•Cuculich et al Circ 2010
Rotor ActivitySpiral waves•Jalife Nature 1998.
Schotten et al Physiol Rev 2011 91 265
Pulmonary Vein FociPulmonary vein triggers•Haissaguerre, NEJM1998
SustainedFocal SourcesSources within the LA•Short AFCL:•Morillio Circ 1995•CFAE:•Nademanee Circ 2004 •High DF sites-•Sanders Circ 2005
Mechanisms of Persistent AF
Persistent AF Is A Disease of Atrial SubstrateExtends from LIPV Inferiorly and Medially Along Posterior LA
Figure 4. Statistical distribution of atrial enhancement over the LA wall. Three-dimensional maps displaying the likelihood of DE over the LA wall template are shown in posterior (1st column) and anterior (2nd column) views in the 4 following clinically relevant subpopulations: no SHD and no AF (1st row, N = 55), SHD and no AF (2nd row, N = 75), paroxysmal AF (3rd row, N = 34), and persistent AF (4th row, N = 26). DE = atrial delayed enhancement; LA = left atrium; SHD = structural heart disease; AF = atrial fibrillation.
Movement of left ventricle during contraction may cause atrial stretch at anchor locations (e.g. pericardial reflections).
Cochet H, et al. Age, Atrial Fibrillation, and Structural Heart Disease Are the Main Determinants of Left Atrial Fibrosis Detected by Delayed-Enhanced Magnetic Resonance Imaging in a General Cardiology Population. J Cardiovas Electrophysiol, Vol. 26, pp. 484-492, May 2015
Pathologic Changes of the Posterior LA
Corradi et al. Nature Clinical Prac CV Med (2008) 5,12
• Presence of interstitial fibrosis has been associated with peAF
• Atrial stretch of the pLA may produce cellular changes which hasten fibrosis.
• The pLA shares embryologic origins with the PV and therefore arrhythmogenic for similar reasons
Posterior Left Atrium (pLA) as an Ablation Target
• Non pulmonary vein triggers in pLACirculation 107 (2003) 3176-3183
• Catheter ablation of frac potentials involving pLACirculation 112 (2005) 3688-3696
• Surgical isolation of pLA improves outcomes in Cox MazeJ Thorac Cardiovasc Surg 135 (1991) 870-7
• Role of the posterior left atrium and pulmonary veins in human lone atrial fibrillation: electrophysiological and pathological data from patients undergoing atrial fibrillation surgery. Circulation 2003;108: 3108–14.
• Proven isolation of pLA improves outcomes in peAFHeart Rhythm 13(1) (2016) 132-40
Esophageal Injury. . . An Electrophysiologist’s Nightmare
J Am Coll Cardiol EP 2017;3:1146–54
“a [mechanical esophageal deviation] >20 mm largely eliminated [esophageal temp elevation]; however, this was achieved in only 22.2% of patients. Three patients did develop clinically significant oropharyngeal discomfort as a result of related trauma.”
Catheter Based Ablation Techniques• 1993 Schwartz Describes PV ectopy as a cause of AF
AHA abstract, Circulation.1993;90:335
• 1998 Haisseguerre Describes PV ablation• 2003 Pappone Wide Area Circumferential Ablation• 2004 Nademanee CFAE ablation• 2005 Haisseguerre Stepwise ablation for peAF• 2008 Haisseguerre Linear lesion sets• 2009 Jackman Ganglionic Plexi• 2004-14 Right atrial ablation• 2012 Narayan Rotor ablation• 2013 Di Biase LAA ablation• Cryoballoon, Contact force, Laser PVI, Mapping
systems . . .
Surgical Management Evolution• Left atrial isolation 1980• His bundle ablation 1982• Guiraudon corridor technique 1985• Cox maze I cut and sew technique 1987• Cox maze II (exclusion of SN), atriotomy moved
to posterior, SVC• Cox maze III septal incision moved posterior to
SVC• Cox maze III made minimally invasive 1999• Cox maze IV bipolar RF box lesion 2004• Unilateral/Bilateral Thoracoscopic ablations +/-
LAA management 2005-2007• Pericardioscopic posterior wall debulking +
Endocardial PVI 2006
Progression of Surgical Lesion Set
*Kiser AC, et al. Simultaneous catheter and epicardial ablations enable a comprehensive atrial fibrillation procedure. Innovations. 2011;6:243-247.
Open Chest EX-MAZE(n = 117)
MIS EX-MAZE(n = 61)
Hybrid EX-MAZE(n = 65)
Progression of Surgical Lesion Set
Surgical Approach with Subxiphoid Entry
14
Saline-Cooled Radiofrequency Ablation of the Posterior Left Atrial
Wall and Pulmonary Veins
Progressive Ablations Guided by EPi-Sense Electrodes
EPi-Sense Technology
• FDA clears the modification in 2013
• Embedded Sensing Capability• Provides real-time feedback to
surgeons
19
Residual Electrical ActivityIdentified by EPi-Sense
Electrodes
No Residual Electrical Activity Confirmed by EPi-Sense
Electrodes
Unablated
Ablated
Before Surgical Lesion SetLSPV
LIPV
RSPV
RIPV
Roof
Mitral Annulus
PosteriorLeft Atrium
Unablated
Ablated
After Surgical Lesion Set
LSPV
LIPV
RSPV
RIPV
Roof
Mitral Annulus
PosteriorLeft Atrium
Unablated
Ablated
After Surgical and Endocardial Lesion Set
LSPV
LIPV
RSPV
RIPV
Roof
Mitral Annulus
PosteriorLeft Atrium
Posterior LA Contributes Minimally to Atrial FunctionPosterior LA Moves Minimally Compared to Rest of Left Atrium
1Kuklik P, et al. Quantitative description of the 3D regional mechanics of the left atrium using cardiac magnetic resonance imaging. Physiol Meas. 2014;35:763-775.
“Figure 2. Example of the LA segmentation. For each cardiac phase, the LA was segmented into six distinct segments. Segments obtained from the short axis projection (a). Roof segment obtained from the four chamber projection (b). The segmental volume taken by each segment is then calculated for each cardiac phase resulting in a plot depicting segmental volume throughout the whole cycle (c).”1
Posterior
Inferior
Posterior Inferior
• The pericardial reflections tether the atrium at the PVs and about the posterior LA limiting movement
• The posterior left atrium contributes least to atrial ejection fraction;
• Any ablation strategy needs to preserve atrial function by targeting lesion creation at low wall motion regions of the LA
baycare.org
Loop Monitoring vs. Holter after Cox Maze III
Circulation. 2009;120[suppl 1]:S177–S184.
• 24 hr Holter failed to detect AF burden of 10% in 50% of cases
• Holter sensitivity was 62%
• Negative predictive value was 64%
Implantable Loop Monitored Patient
Outcomes at Last Follow-Up 12 months
0%
20%
40%
60%
80%
100%
% Sinus Rhythm% Sinus Rhythm,
No Class I/III AADs % Sinus Rhythm,No Class I/III AADs,
No Interventions% Repeat Catheter
Ablation
98%84%
75%
11%
Makati KJ Sherman A. HRS 2015
Outcomes at Last Follow-Up 48 months Using Continuous Loop Recorder
Makati KJ Sherman A. HRS 2017
0%
20%
40%
60%
80%
100%
AF Burden <1% AF Burden <5% AF > 30 sec *
70%84%
66%
baycare.org
Hybrid Off Pump PVI, Atriclip, Numeris Box with Endocardial Cryo and Cavotricuspid Line
baycare.org
Hybrid Off Pump Bipolar Clamp PVI, Atriclip, Numeris Box with Endo Cryoballoon Touch up and Cavotricuspid Line
After Bipolar Clamp, Numeris, and Atriclip After one 100 sec Cryoballoon application at the RIPV
Conclusions• Convergent ablation provides a
comprehensive posterior wall isolation using a truly minimally invasive approach
• Endocardial + epicardial ablation provides durable lesion sets
• Despite extensive atrial debulking, no significant compromise in atrial function has been observed.
• Randomized prospective data is forthcoming
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