THERAPUETIC OPTIONS FOR AFIB: CATHETER ABLATION

SAMBIT MONDAL, MDCARDIAC ELECTROPHYSIOLOGIST

AFLUTTER REVISITED

•AFLUTTER - RIGHT ATRIAL PRIMARILY

•AFIB - LEFT ATRIAL PRIMARILY

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Drug therapy vs first-line ablation for atrial flutter

61 patients> 1 episode of atrial flutterno prior antiarrhythmic drugtherapy

Antiarrhythmic DrugTherapysotalol, amiodaroneflecainide, procainamide,propafenone

RF Ablation> 90% reduction inelectrogram amplitudealong ablation line

Atrial Flutter Recurrence:

Atrial Fibrillation:

Sinus rhythm last f/u

93%

60%

36%

6%

29%

80%

mean follow-up: 22 months Natale et al J Am Coll Cardiol 2000

CLASSIFICATION• Paroxysmal

• recurrent - at least 2 episodes

• terminates spontaneously within 1wk

• Persistent

• doesn’t terminate within 1wk or

• requires cardioversion to convert within 1wk

• Permanent / chronic

• > 1yr duration

> 2.2 MILLION in USA have AFIB

•AFFIRM TRIAL RACE TRIAL

N Engl J Med 2002; 347:1825-33 and 1834-40, Dec 5,2002

RATE VS RHYTHM CONTROL

AFFIRM- efficacy of antiarrhythmics

AFFIRM TRIAL•3/4 normal EF

•Mortality difference mainly due to non-cardiovascular and cancer deaths

•No difference in the rate of cardiovascular events - including stroke.

• Presence of sinus rhythm reduced mortality significantly, however anti-arrhythmics seemed to increase mortality by 49% : beneficial effects of SR may be offset by anti-arrhythmics

•DIAMOND study confirmed the above hypothesis.

OPTIONS FOR RATE CONTROL

•MEDICATIONS

•AV NODAL ABLATION

•last option

•doesn’t eliminate symptoms of afib

•permanent dependancy on PM

•6.3% 1-yr mortality : 2% risk of SCD

•BiV vs single chamber pacing ( PAVE )

so which is better ?rhythm or rate

control

PROVEN DATA

•independent predictor of mortality

•valvular heart disease

•post CABG

•heart failure

•decrease survival

RHYTHM CONTROL•quality of life improved significantly

with rhythm

•mortality data not available

•stroke risk data pending long term studies

•progression to heart failure decreased by rhythm control

•hospital admission / overall cost reduced by rhythm control

NATURAL HISTORY

paroyxsmal

lone fib

perst/perm

50%

40%

CATH ABLATIONSINUS RHYTHM

Heart rhythm Pappone et al. Nov 08:5:11:1501-1507

RACE FOR A CURE

•THE HOLY GRAIL

PATHOPHYSIOLOG

Y•multiple wavelet theory Moe et al. 1980’s

•multiple reentrant circuits which requires critical mass of atrial tissue to sustain itself

•basis for cut and sew Cox-Maze procedure to reduce critical mass

• version I, II and now III

•atrial transport function

•difficult to perform - didn’t gain popularity

2003/2004 Pappone et al.

PATHOPHYSIOLOGY

•cardiac autonomic nervous system and its relationship with triggered spontaneous electrical firing - Jackman et al.

•current understanding of triggers, rotors, substrate and autonomic interactions

PATHOPHYSIOLOGY• atrial muscle sleeve into the pulmonary veins

as trigger sites

• APD and ERP within the pulmonary veins shorter than LA tissue

• slower conduction of tissue towards atrio-pulmonary junction leading to variable block and micro re-entry.

• areas of slower conduction marked as fractionated potentials

• more fractionation seen with increased in LA pressures

PATHOPHYSIOLOGY•areas of micro-reentry at the sites of

slowed conduction : rotors at LA-PV

•not clear what causes triggered activity within pulmonary veins

•atrial remodelling : “afib begets afib”

•LA-RA electrical heterogeneity and gradient

PATHOPHYSIOLOGY

•spectral analysis : dominant frequency stimulation sites within pulmonary veins in paroxysmal afib.

•chronic afib: no dominant frequency seen.

•chronic afib: atrial remodelling plays a more dominant role

PATHOPHYSIOLOGY

•nearly 1/3 paroxysmal ( unselected population) : non PV triggers

•non PV triggers : post LA, fossa ovalis, SVC, crista terminalis, ligament of Marshall, AV junction, coronary sinus

•4% SVT initiating Afib : AVNRT, AVRT

PAROXYSMAL AFIB PERSISTENT / CHRONIC AFIB

antiarrhythmicscardioversion with antiarrhythmics

feel better in SR no difference

rhythm control

rhythm control with meds only and if not possible then RATE

CONTROL

recurrence

RHYTHM CONTROL SCHEMA

ACC/AHA/HRS GUIDELINE UPDATE FOR MANAGEMENT OF AFIB 2006

MAINTAINENCE OF SINUS RHYTHM

AMIODARONEDOFETILIDE

ABLATION

FLECAINIDEPROPAFENONE

SOTALOL

NO HEART DISESE

ABLATION

AMIODARONE

SUBSTANTIAL LVH

AMIODARONE ABLATION

SOTALOLDOFETILIDE

CAD

ABLATION

AMIODARONEDOFETILIDE

HEART FAILURE

ANTICOAGULATION• CHADS 2 RISK SCORE:

• Congestive heart failure

• Hypertension

• Age greater than 75

• Diabetes Mellitus

• Stroke or any thromboembolic phenomenon

CHADS SCORE

0 - ASA

1- ASA OR COUMADIN

>1 or high risk markers COUMADIN

ABLATIVE OPTIONS

•CATHETER BASED

•SURGICAL - CONCOMITANT

•SURGICAL STAND ALONE

• “MINI MAZE”

INDICATIONS

•SYMPTOMS

•FAILED ≥ 1 ANTIARRHYTHMIC

•EF >40%

•AGE < 80 YRS

SYMPTOMS

•fatigue “sleeps off as soon as lay on the couch in the evenings” - under-recognized

•dyspnea on exertion

•palpitations “heart skipping”

•chest pain

•“just don’t feel right”

CATHETER ABLATION

•It is not a substitute for coumadin therapy and to attempt ablation aiming primarily at stopping coumadin therapy is INAPPROPRIATE

•All patients will continue coumadin therapy post ablation

•IT IS NOT A CURE, BUT A TREATMENT APPROACH - much akin to CAD/stent.

•applies to surgical ablation also

SUCCESS RATES

•PAROXYSMAL AFIB : > 70-80%

•PERSISTENT AFIB : >60-70%

•CHRONIC AFIB : 50-60%

•SUCCESS AT 6MONTHS

•POST PROCEDURE RECURRENCE OF ARRHYTHMIA IS COMMON AND NOT A SIGN OF FAILURE - atrial remodelling 3months

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CFAE MAPS•complex fractionated atrial electrogram

•0.06 - 0.25V, >120ms

•represent areas of slow conduction / micro-reentry

•correlate with epicardial ganglionic plexi

•important in persistent and chronic cases

ICE

•intracardiac echo imaging

•5.5-10MHz, depth 2-12mm

•transeptal puncture, defining LA structures, pulmonary vein anatomy, location of circular catheter, complication detection and management

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POST ABLATION•follow up

•2wk - 12 lead EKG

•1month - 24 hour holter

•3months - 1 month AFib monitor ( decision to take off antiarrythmics)

•6month - 1 month Afib monitor ( decision to take off coumadin if CHADS score <2)

RECURRENCE• recurrences of atrial fibrillation / atrial tachycardia / left atrial

or right atrial flutter

• recurrences more common within the 1-3month period

• inflammatory / stimulating effect of thermal injury

• imbalance of autonomic nervous system

• delayed effect of growth and maturation of lesions

• factors favoring recurrences

• age

• BMI

• paroxysmal vs persistent vs chronic

• size of left atrium

• structural heart disease

RECURRENCE

•reconnection PV-LA

•additional triggers

•macro-reentrant tachycardia

•autonomic influences

COMPLICATION• cardiac tamponade - upto 3%

• pulmonary vein stenosis - 1-3%

• chest pain / dyspnea / recurrent lung infection / pulmonary hypertension

• atrio-esophageal fistula - 0.25%

• fever / chills / hemoptysis / recurrent neurological events

• phrenic nerve injury - <0.5%

• hiccups / dyspnea / atelectasis / pleural effusion / cough / thoracic pain

• Thromboembolic events / air embolism / stroke

• vascular complication

• acute coronary occlusion

• peri-esophageal vagal injury - pyloric spasm / gastric hypomotility

• fluroscopy related injury

• mitral valve entrapment of circular catheter

SURGICAL ABLATION

COX MAZE• James Cox 1987

• extensive cut and sew to interrupt the reentrant circuits

• technically challenging and time taking

• long term success rates good however few CT surgeon willing to perform the full cut and sew Maze

• numerous iteration have been developed. Final version Cox Maze III.

• linear lines of ablation developed with unipolar sources of energy

ENERGY SOURCES

•unipolar energy source

•microwave / radiofrequency / HIFU / cryo / laser

•bipolar energy source

•radiofrequency

SURGICAL ABLATION

•full Cox Maze procedure ( Maze III )

•LA ablation sets

•pulmonary vein isolation

SURGICAL ABLATION•INDICATIONS:

•concomitant procedure - both symptomatic and asymptomatic patients

•stand alone minimally invasive ( mini Maze)

•prefer surgical approach

•failed one or more attempts at catheter ablation

•not candidates for catheter ablation

Mini - Maze

multi-speciality approach

•primary care physicians

•cardiologist

•cardiac electrophysiologist

•cardio-thoracic surgeons

“Watchman” left atrial occluding device

Maisel W. N Engl J Med 2009;10.1056/NEJMp0903763