Catheter Ablation for AF: Patients, Procedures, Outcomes

John Sapp

Director Heart Rhythm, QEII Health Sciences CentreProfessor of Medicine, Dalhousie University

Atrial Fibrillation

Atrial Fibrillation is a pain in the rear….

What makes it so difficult?

Goals of Care?

Live longerand / or

Live better

How can AF hurt your patients?

• Symptoms

• Stroke/Thromboembolism

• Tachycardia-induced cardiomyopathy

The indication for rhythm control is inadequate symptom relief with rate control

How to Pick Rhythm Control

• The main goal is symptomatic control

Which one is better?

Liparus Weevil

Pissodes pini Weevil

How To Choose Rate Vs Rhythm Control?

The Devil you know?

Rate ControlBeta-blockersCa++ Channel BlockersDigitalis

Rhythm ControlAF Ablation

Amiodarone, Sotalol, Flecainide, Propafenone,Dofetilide, Dronedarone

Young patients?Athletes?

Resting Bradycardia?

?

How to rate control

• Beta-blockers• Verapamil / Diltiazem

• Digoxin? Not dronedarone• Sometimes pacemaker to permit drug therapy• Rarely AVN ablation

How to Rate Control

• Target resting HR < 100– Sometimes a treadmill test or loop recorder is

informative…

• Pill in the pocket rate control and anticoagulation?

Rhythm Control

• Special cases for rhythm control:– Heart failure?– Young age– Highly symptomatic– Resting bradycardia / Athletes

Rhythm Control• Sotalol

– Avoid in elderly women, use of diuretic, renal dysfunction, hypokalemia, prolonged QT

– I start at 80-120 bid…not higher than 160 bid• Flecainide

– Avoid in patients with ventricular scar– I start at 50 mg bid, sometimes 100 bid, rarely

150bid• Propafenone

– Avoid in patients with ventricular scar– I start at 150 bid-tid, rarely 300 tid

Rhythm Control

• Sotalol: Monitor renal function over time, check QTc interval intermittently, concern if >470, reduce dose if >500

• Flecainide: Watch for side-effects—QRS widening, other

• Propafenone: Watch for side-effects—QRS widening, other

Rhythm Control

With Flecainide / Propafenone,

I always use an AV node

blocking agent

Catheter Ablation for AF

• Triggers

• Substrate

Who Should Have Ablation?

Risks

• 4.7% Complications – 1.5% vascular– 1% Perforation/Tamponade– 1% Stroke/TIA

• Rarer Complications– Pulmonary vein stenosis– Phrenic nerve injury– Atrio-esophageal fistula / Death

Redo Rates

• Seems to be changing…– Was approximately 1 in 3

– Moving closer to 1 in 4-5….

Ablation Procedure

Ablation Techniques

• Radiofrequency Ablation– Double trans-septal puncture– Point-by-point ablation lesion delivery

encircling the pulmonary veins and electrically isolating them

Andrade et al. CJC 2014; 30 S431-S441

Contact Force Sensing Catheters

TOCCASTAR

Reddy et al. Circulation Sep 2015

Recurrence at areas of low force < 10g

CryoAblation

• Liquid-Nitrogen-cooled balloon

• Advanced across interatrial septum, and inflated in pulmonary venous ostia

STOP-AF Trial: Cryoablation

Catheter Ablation for Persistent AF

• Patients with persistent AF have lower success rates with catheter ablation than paroxysmal patients…

Ablation for Persistent AF

Trials to come…• Comparisons of Cryoablation against RF

ablation

• Comparison of cryoablation against antiarrhythmic drug therapy as an early intervention

• Comparison of AF Ablation versus drug therapy with clinical endpoints

Longer Term Outcomes

• Most recurrences occur within the first year after ablation

• Late recurrences:– 87% 1 year, 81% at 2 years, 63% at 5 years…– 85% at 3 years, 75% at 5 years

• Focus still remains on ablation to control AF, not necessarily a cure…

AF Ablation in Heart Failure

Hsu, NEJM 2004

LVEF LV Fractional Shortening

LVEDD LVESD

Freedom from AF after AF ablation in patients with LV dysfunction

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Hsu (N=58)

Chen (N=94)

Gentlesk (N=67)

Khan (N=41)

Lutomsky (N=18)

Efremids (N=13)

Choi (N=15)

De Potter (N=36)

MacDonald (N=22)

Hunter (N=26)

AF Free post-ablation

RAFT-AF

• Hypotheses• Catheter ablation-based AF rhythm control as compared with rate

control in patients with HF of either impaired LV function (LVEF ≤ 45%) or preserved LV function (LVEF > 45%) will reduce all-cause mortality or HF hospitalization

• Key Inclusion Criteria:• High burden AF – paroxysmal, persistent, long-term persistent• NYHA class II or III HF• Increased NT-proBNP/BNP

• Intervention:• Rhythm control arm: Catheter ablation ± AAD• Rate control arm: Rest HR<80; 6MW HR <110

Conclusions

• Rhythm control is still directed at symptoms• First-line therapy is still usually antiarrhythmic

drug therapy• I think new technology is improving the

single-procedure success rate• New trials will help us know best technology

for ablation, and role for ablation in heart failure patients with AF

Conclusions

• AF Ablation works best for patients with:– Paroxysmal atrial fibrillation– Normal hearts

• Less appropriate for– Very elderly– Longstanding persistent AF– Diseased atria, size > 50 mm…