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Update in Internal Medicine
Atrial Fibrillation: To Treat or Ablate?
Samir Saba, MD, FACC, FHRSProfessor of Medicine
Division Chief, CardiologyCo-Director, Heart and Vascular Institute
Disclosure
Research Support:ØNHLBIØBoston ScientificØMedtronic Inc.
Intellectual Property:ØMedtronic Inc.
OutlineØThromboembolic protectionØAF Management
vRate Control StrategyvRhythm Control Strategy
ØThe past, present, and future of ablation for paroxysmal and persistent AF
ØGuideline Recommendations
Atrial Fibrillation
• Demographics of AFv A heterogeneous population
• General concerns with AF:v Thromboembolismv Symptomsv Myocardial function
• Strategies of Management:v Rate controlv Rhythm control
qAblation
Presentations
Mr. DMØ87 year old manØh/o CAD and LAD stent in 2003ØStroke in 2007ØHad syncope while urinating in
the bathroomØPresenting rhythm is AF with
VRR 70 bpmØNo palpitations, CP, or SOB
Mr. JLØ45 year old manØNegative cardiac historyØWoke-up from sleep with severe
symptoms of palpitations and SOB
ØDrank 6 beers the night beforeØWas in AF with VRR 145 bpmØConverted spontaneously to SR
while in ER
Demographics
Maisel WH et al. Am J Cardiol 2003;91:2D-8D.
Demographics
Lone AFYounger
No heart diseaseNo PVDNo HTNNo DM
No stroke/TIALow CHADS2vasc
AF with Comorbidities
OlderCHF/heart disease
PVDHTNDM
Prior stroke/TIAHigh CHADS2vasc
HIGHER RISK (mortality, stroke, etc…)
LOWER SUCCESS IN MAINTAINING SR
Paroxysmal AF Persistent AF Permanent AF
General Management of Atrial Fibrillation
ØFor decades, the mechanism of AF was perceived to be a chaotic rhythm with no focus to ablate
ØThe main stay of therapy was: vOral anticoagulationvRate control medicationsvRhythm control medicationsvRare ablation of SVT mechanism, possibly implicated in AF
initiation
1. Thromboembolic PreventionØMechanisms of thromboembolism include:
v Stasisv Hyper-coagulable state
Ø Clots form mainly in LAA but can be anywhere in the LAØStroke:
vRisk of stroke increase by 3-5 folds in AFv 15% of all strokes are attributable to AFvRisk higher with higher CHADS2vasc scorev Except for patients at lowest risks (score 0 or 1), or those with
major bleeding complications (brain, retina, massive GI, etc…), anticoagulation is indicated
Thromboembolic PreventionØAnti Platelets (Aspirin, Clopidogrel, Ticaglecor)
ØAnticoagulation
vWarfarin
vDOACs only in NVAF (Dabigatran, Rivaroxaban, Apixaban, Edoxaban, Betrixaban)
ØCHA2DS2-Vasc score
CHA2DS2-VASc Score
Annual Stroke Risk (%)
0
1 1.3
2 2.2
3 3.2
4 4.0
5 6.7
6 9.8
7 9.6
8 12.5
9 15.2
LAA Closure
Reddy VY et al. Circulation. 2013;127:720-729
2. Symptoms
Ø Some patients are asymptomatic Ø Symptoms may include: palpitations, SOB, DOE, CP, dizziness,
fatigue, etc…Ø Attributing symptoms to AF may be difficultØ Symptoms may be due to:
v Irregular ventricular ratev Rapid ventricular ratev Loss of atrial contraction (‘atrial kick’)
3. Tachycardia-Induced Cardiomyopathy
ØIf VRR is persistently fast for long periods of time this may lead low EF
Ø This form of cardiomyopathy is reversible: with good rate control, the EF is expected to normalize
Ø It is often difficult to ascertain whether the rapid AF led to CMP or the CMP resulted in rapid AF (the ‘chicken or egg’ dilemma)
Ø Confirmation is made after few weeks of controlling the ventricular rate of AF or after restoring and maintaining SR
Management of AF: Rate Control Strategy1. Digoxin2. Beta Blockers3. Calcium Channel Blockers4. AVN ablation with Pacemaker
Management of AF: Rhythm Control Strategy
ØSodium Channel BlockersvFlecainidevPropafenone
ØPotassium Channel BlockersvSotalolvDofetilide
ØAmiodaroneØCardioversion +/- DrugØAF Ablation
Choice of Strategy
ØThere is no right or wrong between Rhythm Control and Rate Control
Ø Choice depends on:vClinical factorsvPatient preference
Ø Often, the choice is empiric, i.e. one would try rhythm control initially, but then settles for rate control after rhythm control fails
Ø How hard one needs to try maintaining rhythm control varies by physician, clinical scenario, and patient preference
Choice of StrategyRHYTHM CONTROL
Goal: restore and maintain SRFactors favoring Rhythm Control:1. Symptomatic AF2. Younger age3. Paroxysmal AF4. Normal heart structure5. No prior attempts at SR6. Smaller LA volume7. High odds of maintaining SR8. Patient willing to undergo
procedures (DCCV, AF ablations) or hospitalizations for initiation of AAD
RATE CONTROL
Goal: accept AF but control VRRFactors favoring Rate Control:1. Asymptomatic AF2. Older age3. Persistent AF4. Abnormal heart structure5. Failed prior attempts at SR6. Larger LA volume7. Low odds of maintaining SR8. Patient unwilling to undergo
procedures (except definitive procedures such as AVN RFA/PM) or hospitalizations for initiation of AAD
Choice of StrategyTrial N F/U Endpoint OutcomePIAF 252 1 year Symptoms NS
STAF 200 20mths Death + thromboembolism NS
RACE 526 2-3yrs CompositeNS
Hot Café 205 1-7yrs Death, stroke, hemorrhage NS
AFFIRM 4060 3-5yrs Total mortality NS
AFFIRM Trial
AFFIRM Trial. N Engl J Med 2002; 347:1825-1833
AF Ablation
Haissaguerre M. et al. NEJM 1998;339:659-666
Historical Evolution of Lesion Set for PVI
ØFocal ablationØIsolation of culprit PV at atrial
junctionØIsolation of two ipsilateral PVs at
atrial junctionØWide antral circumferential
ablation of 4 PVs (WACA)
Paroxysmal Atrial Fibrillation
Two approaches:ØPoint-by-point
delivery of lesionsØSingle application
lesions
AF ablation = PVI1-year freedom from AF~75-80%
STOP AF TrialØN=245 patients with PAF failing ≥ 1 AADØRandomized 2:1 to
• Cryoballoon PVI (n=163) • Medical therapy (n=82)
Ø90 day blanking period to adjust AADØ12-month follow-upØPrimary endpoint is freedom from AF
recurrenceResults:Ø4 PV isolated in 97.6% of patientsØSixty five (79%) of Medical therapy
patients crossed over to ablation arm within 12 months
Packer D et al. JACC 2013;61:1713-1723
STOP-AF Post Approval StudyØ39 CentersØ345 patientsØ5.7% complications
o Vascular bleeding – groin or retroperitoneal
o Pseudoaneurysm, AV fistula
o Pericardial effusion or tamponade
o Phrenic nerve injury
o Stroke, thromboembolic event
o Atrio-Esophageal Fistula
Total Major Complications in 450 cases 10 2.2% Persistent Phrenic Nerve Injury 5 1.1%
Symptomatic Pericardial Effusion 3 0.67% Deep Vein Thrombosis 1 0.22%
AV Fistula 1 0.22% Bleed/Hematoma Requiring Transfusion 0 0%
Stroke 0 0% Death 0 0%
Phrenic Nerve Injury 49 10.8% Temporary Phrenic Nerve Injury 44 9.7% Persistent Phrenic Nerve Injury 5 1.1%
Long-Term Phrenic Nerve Injury 0 0%
Guhl E. et al. J Am Heart Assoc. 2016 Jul 21;5(7).
Fire and ICE Trial
Kuck KH et al. N Engl Med J 2016; 374;23:2235-2245
Ø 762 patients with PAF• RFA• Cryo-balloon
Ø Follow-up 1.5 yearsØ Efficacy
• Recurring AF• Aflutter/AT• Use of AAD• Redo Ablation
Ø Safety• Death• CVA• Other serious AE
Persistent Atrial FibrillationWith PVI alone, 1-year freedom from AF~50-60%
PVI + What Other Lesion Set(s)?ØCavo-tricuspid isthmus ablationØRoof line and mitral isthmus lineØGanglionic plexi ablationØRotor mapping and ablationØComplex atrial fractionated electrograms (CAFÉ)ØPosterior LA wall isolation (posterior box)ØHybrid procedures with surgical epicardial and EP endocardial
approach
Ablation of Epicardial Ganglionic Plexi for AF The AFACT Study
ØN=99 with PAF• PVI + GP ablation• PVI
ØN=141 patients with long persistent AF• PVI + lines + GP ablation• PVI + lines
ØPrimary endpoint was 1 year freedom from AF
Driessen AHG et al. JACC 2016;68:1155-1165
STAR-AF II TrialØ589 patients with persistent AF
ØPVI aloneØPVI + CAFÉ ØPVI + Mitral isthmus + Roof lines
Verma A. et al. NEJM 2015;372:1812-1822
Posterior LA wall Isolation
Saad EB et al. J Atr Fib. 2014 ; 7: 1174Kim JS et al. Int J Cardiol 2015;181:277-283
ØN=120 patients with PeAFØRandomized to:• PVI + linear lesions• PVI + linear lesions + PWI
Ø Primary endpoint is AF-free survival
Posterior LA wall Isolation
ØMulticenter study of 390 patients with persistent AF at 6 centers from 2014-2017ØPhase 1: 222 patients underwent PVI+PWI; Phase 2: 168 patients underwent PVI onlyØSame operators performed procedures in both phasesØCryoballoon used for PVI and for PWI
PVI Only PVI + PWI FREEDOM from AF/AFL
Aryana A. et al. Heart Rhythm 2018; 15:1121-1129
PVI + PW Isolation
BEFORE AFTER
AF-FICIENT Trial• Presented at AF Symposium 2017• Multicenter, non-randomized, pilot• Met safety endpoint at 7 and 30 days• 98% PV isolation success rate• Average LA time of 39 min• 80% freedom of AF at 6 months
ØIndividual adjustment of powerØover-the-wire 28mm balloon
with 12 proximal and six distal electrodes to map and ablate.
ØBuilt-in cameras to provide real-time visualization of electrode contact to the tissue
New Technology: Radiofrequency Balloon for AF Ablation
New Technology: HotBalloon Ablation for PAF
ØRandomized (2:1) trial of HBA
vs. AAD
ØRF energy is used to heat the
liquid (saline/contrast) inside
the balloon which transmits
thermal energy to the tissue
ØRF generator automatically
controls the temperature
between 40-70o C
ØA vibratory agitation device
continuously mixes the fluid
to maintain a uniform
temperature in the balloon
Sohara et al. JACC 2016;68:2747-2757
Laser Balloon for PVI
J Cardiovasc Electrophysiology 2013;24:987-994.
The Cabana TrialØN=2,204 patients randomized
to ablation versus medical therapy (2009-2017)
ØAblation• PVI+/-GP, Linear, CAFE• OAC
ØMedical therapy• Rate control • Rhythm control• OAC
ØPrimary endpoint is composite of death, stroke, bleeding, or cardiac arrest
Packer DL et al. JAMA 2019;321:1261
However:Ø ITT analysis negative but with significant crossover
• 9.2% of ablation patient did not receive the ablation• 27.5% of medical therapy patients underwent ablation
Ø On treatment analyses showed significant advantages of ablation• 33% relative reduction in primary composite endpoint• 40% reduction in all-cause mortality
Ø The real goal of AF ablation is to improve AF symptoms
AF Ablation in Heart Failure PatientsCASTLE-AF Trial
ØN=363 HF patients with PAF or persistent failing ≥ 1 AAD
ØAll patients had:• NYHA class II, III, IV• LVEF ≤35%• ICD implanted
ØRandomized 1:1 to• AF ablation (n=179) • Medical therapy (n=184)
ØMedian follow-up 37.8 monthsØPrimary endpoint is death or HF
hospitalization
Marrouche NF et al. N Engl J Med 2018; 378:417-427
Outcomes of AF Ablation ProceduresØImprove patients’ symptoms and QOL
ØIn patients with CHF, AF ablation decreases the composite endpoint of death or hospitalization for heart failure
ØAF ablation does not decrease the risk of stroke or thromboembolic eventsClass III: Harm1. AF catheter ablation should not be performed in patients who cannot be
treated with anticoagulant therapy during and following the procedure. (Level of Evidence: C)
2. AF catheter ablation to restore sinus rhythm should not be performed with the sole intent of obviating the need for anticoagulation. (Level of Evidence: C)
ØAF ablation does not prolong life in all-comers
Rhythm Control for AF
January et al. AHA/ACC/HRS Guideline for the Management of Patients with Atrial Fibrillation. JACC 2014: 2246-80.
‡ Based on patient’s preference and institutional experience
Future Directions in AF Ablation Therapies
ØBetter tools for single application ablations (circular and linear) with new energy sources
ØBetter understanding of the value of additional/adjunctive therapies to improve effectiveness of AF ablation
ØHybrid approach to AF ablation endocardially (EP lab) and epicardially (CT surgery)
ØFurther expanding of the ablations to sicker patients who may extract more benefit from it
Questions?