Rotor Mapping A FIRM Foundation Exists John M. Miller, MD Professor of Medicine Indiana University School of Medicine Krannert Institute of Cardiology Director, Clinical Cardiac Electrophysiology ~ Disclosures ~ Medtronic, Inc.; Boston Scientific Corp.; Biosense-Webster, Inc.; Biotronik, Inc. (Training support; Lecturer); St. Jude Medical (Lecturer) Stereotaxis, Inc.; Topera, Inc.(Advisor Board)
Recipe for Arrhythmias Trigger (initiators) + Substrate (maintenance) Arrhythmia
Recipe for Arrhythmias PAC/PVC (initiators) + WPW Circuit (maintenance) Orthodromic SVT
Recipe for Arrhythmias Drivers PAC fr. PV (initiators) +??????? (maintenance) Atrial Fibrillation
The Spin on Rotors Using special analytical algorithms, Narayan observed first stable rotors in man (2005) Sites of complete rotation Spatially stable over several cycles (some precession within a domain ) 1-3 cm 2 area Multiple rotors may be operative at same time - May be in same or opposite atrium - Playing off each other, giving rise to very complex activation patterns Focal sources (automatic/triggered activity vs microreentry) may also be present
Right Anterior Oblique Left Anterior Oblique Basket Cases Right Atrium Left Atrium
Basket Cases
Rotor Mapping and Ablation 43 yo man Left atrial basket Rotor posterior to left carina CL 140 ms (~430/min) Outside prior WACA
Rotor Mapping and Ablation ~5 sec
FIRM-Discovered AF Sources Rotors or focal sources: Found in >98% of cases paroxysmal = others Locations: - Near PVs in 23% - LA roof/anterior wall in 21% - Other LA sites in 20% - RA sites in 33% Ablation at these sites slows/stops AF in 83%: - Slows by >10% in 27% - Terminates to AT in 17% - Terminates to SR in 38% (including persistents) Long-term freedom from AF when ablated in 82%
CONFIRM Results vs Other Trials (88% CIED Follow-up) STOP-AF, 2012 (PAF) RAAFT-2, 2012 (PAF) Weerasooriya, 2011 (25% (2/3 CIED PAF, 1/3 Followup) PeAF) N=107 cases; N=92 patients Narayan, Krummen Shivkumar, Miller et al., CONFIRM. JACC 2012; 60(7): 628-636 Morillo, Natale et al., RAAFT-2, LBCT HRS 2012; Weerasooriya, Haïssaguerre, JACC 2011
Other Aspects CONFIRM results confirmed in other centers: 14 centers outside San Diego have experience - Same distribution of sources (RA/LA; rotor/focus) - Same acute slowing/termination results - Slightly more paroxysmals than in CONFIRM - Shorter follow-up than in CONFIRM More FIRM procedures have now been performed outside San Diego than in San Diego
But Why Does WACA Work? WACA appears to work by FIRM elimination: On-treatment analysis of CONFIRM (94 cases): - AF sources directly ablated (FIRM-guided) in 100% - AF sources coincidentally ablated by WACA in 45% Authors compared FIRM sites to WACA lines: - WACA/roof lines passed through all FIRM sources - WACA/roof lines passed through some FIRM sources - WACA/roof lines passed through no FIRM sources Long-term freedom from AF when ablated in 82%
Why Does WACA Work? Hit!
Why Does WACA Work? Hit!
Why Does WACA Fail? Miss!
Event-Free Survival Why Does WACA Work? 1.0 Freedom from Atrial Fibrillation All Cases p < 0.001 1st Ablation p < 0.001 0.8 0.6 0.4 Not through source Through source Not through source, 1st ablation Through source, 1st ablation 0.2 Number at Risk 0.0 0 200 400 600 800 Days 33 13 8 4 3 Not through source 61 46 28 20 11 Through source
Event-Free Survival Why Does WACA Work? Freedom from Atrial Fibrillation 1.0 0.8 p = 0.080 0.6 0.4 p = 0.025 p < 0.001 0.2 0.0 Number at Risk None Some All 0 200 400 600 800 Days 24 9 6 2 2 12 6 4 3 2 33 26 12 7 1 All None Some
It Just Goes to Show I m SOOOO good at this!!
Right Atrial Sources How important is the right atrium in AF? Initial reports of AF ablation concerned RA sites Early attempts to replicate surgical maze lesions with catheters included RA lines Since PVs became targets, RA has been ignored Recent work has resurrected the RA - ~30% of patients have a right atrial focus/rotor - ~15% of patients have only RA sources Implications - RA should not be ignored, but explored - Map RA first, if AF terminates and is rendered noninducible, perhaps no need to enter LA
Right Atrial Source ~5 sec
Right Atrial Source
Many questions remain: Rotorology What is the milieu that makes a rotor? - Structural/ultrastructural vs functional changes, or both Why do rotors and foci occur where they do? - Not random, but not just anywhere What constrains a rotor s mobility? - Structural vs functional changes, or both Why do rotors remain stable (not decay)? - Nature doesn t like metastability Can new rotors develop over time? - If so, can we learn how to target areas preemptively during sinus rhythm?
How Can a Rotor Stay Stable Over Time? Voyager 1 Approaches Jupiter (1979) Red Spot 1 st seen by Galileo 1610
Next Steps: FIRMAT What is the role of FIRM in AF ablation? FIRM adds value in concurrent/prior PVI cases - Enhanced efficacy - AF termination, improved long term freedom from AF - Widespread applicability (paroxysmal, persistent, LPAF) FIRM could be beneficial for process - Possibly less extensive ablation - Possibly faster procedures - Possibly less likelihood of PV stenosis, LA macroreentry Needed: Randomized trial of FIRM vs other method - FIRMAT: FIRM only vs WACA in PAF - 12 US sites, targeting 188 patients (1:1 randomization) - IRB approval at IU 5/2/13
Summary Focal impulse and rotor modulation: Is strongly founded in basic science Is reproducible/stable over time Has been replicated in multiple laboratories Is validated by: - Acute slowing or termination of AF (to AT or NSR) - Intermediate term follow-up free from AF And thus has a FIRM foundation Please stay tuned