Southeast Regional Heart and Vascular Symposium for Primary Care Providers
Atrial Fibrillation Modern Therapies Gregg Shander, MD, FACC
No Disclosures
AF Epidemiology • Number of AF patients world-wide estimated at 33.5 million (0.5 % of world’s population) • Currently there are 5 million new cases worldwide per year and it is expected to increase to over 12 million by 2030 • Approximately 5 million cases of AF in the U.S. • Lifetime risk of AF in pts > 55y.o. is approx. 25%
AF Epidemiology • Aging population is the biggest factor for increasing AF prevalence • Prevalence of AF – 0.16% < 49 y.o. – 3.7% 60-70 y.o. – 10% > 80 y.o.
Comorbidities Associated with AF • • • • • • •
CAD Hypertension Obesity Sleep Apnea CHF COPD Renal Failure
Patterns of Atrial Fibrillation • Paroxysmal •
< 1 wk, often < 24hrs. Usually terminates spontaneously
• Persistent • > 1wk but < 1yr. Usually requires cardioversion
• Permanent • > 1 yr. Usually refractory to meds and cardioversion
Atrial Fibrillation Begets Atrial Fibrillation
Action Potential changes with Chronic Atrial Fibrillation
Progressive Atrial Fibrosis with Persistent Atrial Fibrillation
Land Masses and Eddy Currents
Models of Re-entry Atrial Fibrillation
Atrial Fibrillation Progression • 4-9% of pts advance to Permanent AF within 1st year • 25% will advance to Permanent AF within 5 yrs. • Detection is challenging – Classic symptoms include palpitations, dizziness, chest pain – More subtle symptoms shortness of breath, weakness • About 1/3 of pts have symptoms 5-10 yrs before detection of AF
Pharmacotherapy for AF • Propafenone, Flecainide – Class Ic agents. Block Na channel – Slows conduction (widens QRS at toxic dosing) – Unable to use in “sick” hearts
• Sotalol – Class III agent. Block K channel – Effects repolarization (prolongs QTc interval) – Can cause Torsades des Pointes – Beta-Blocker slows HR – Cleared by kidneys – Dofetilide – Class III agent, also blocks K channel and lengthens repolarization – Does not slow HR – Requires a 3 day hospital stay for loading due to risk of pro-arrhythmia (Torsades)
Pharmacotherapy for AF • Amiodarone – – – – –
Non-Specific alters many channels “Dirty-Drug” goes throughout the body Side-effects increase over time Not FDA approved for AF Probably our most effective and safest drug in sick hearts
• Dronaderone – Amiodarone-like – Initially promising (ATHENA Trial), then warnings about deaths in cardiomyopathy pts with permanent AF (PALLAS Trial) – Effectiveness in real-world seemed less than clinical trials
Problems with Pharmacotherapy • Unable to use in many less healthy patients – Cardiomyopathies – CAD – Renal Insufficiency – Bradycardia – Often Ineffective. Except for Amiodarone, efficacy less than 40% by one year
AFFIRM Trial • Mortality Trial • 4000 pts • Over 65 with at least one risk factor for stroke or early death e.g. CAD,Htn • Compared Rate vs Rhythm Control (any A.A.) strategies • Results: No significant difference in either mortality or stroke between the two strategies. A trend toward increased mortality with A.A. drugs • Conclusion: Rhythm Control is equivalent to Rate Control in terms of mortality
Origins of Atrial Fibrillation Ablation
AF Ablation Set-Up • General Anesthesia, Intubation and mechanical ventilation • 6 venous catheters and 1 arterial insertion • 2 trans-septal punctures use of intracardiac ultra-sound • RF ablation catheter and circular mapping catheter in the left atrium • Esophageal temperature probe • Delivery of 40-60 lesions in the left atrium • Procedural times of between 2.5 and 4 hrs
Potential Complications from AF ablation • Groin complications (hematoma, A-V fistula, pseudoaneurysm) • Cardiac tamponade 0.5% -3% • Stroke 0.5%-1.5% • Asymptomatic cerebral emboli 5-10% • Pulmonary vein stenosis 1% • Phrenic nerve injury 0.5% RF, 11% cryo-ablation • Esophageal-atrial fistula 1/750-1000 • Death 1/1000
ICE and Fluoroscopic Images of AF Ablation
Radiofrequency lesions around Pulmonary Veins
Pulmonary Vein Isolation
Thermocool AF Trial • 167 pts. 2:1 Ablation to A.A therapy excluding Amiodarone • After a 3 month blanking period, data collection of 9 months by transtelephonic monitoring • Success = No symptomatic or asymptomatic documented AF episodes • Results: – 66% success with ablation – 16% success with A.A. therapy
Smart Touch Trial • Smart Touch Catheter • Pressure sensitive measured in grams of force • If > 80% of lesion delivery time had “sufficient force”, then efficacy of ablation increased from 66-82%
STAR AF 2 Trial • Persistent Atrial Fibrillation (76% >6mos) • 589 patients, 12 countries • Randomised to different ablation strategies – PVI vs PVI w/ Linear Ablation vs PVI w CFE – f/u 18 mos utilizing ILR – Failure = Afib > 30 sec – No significant difference between ablation strategies. PVI alone the best at 59% success.
Catheter Ablation vs Antiarrhythmic Drug Therapy (CABANA Trial) • Determine freedom from AF in Drug (rate or rhythm control) vs ablation in patients with comorbidities or age > 65 • Persistent and paroxysmal AF • Assess mortality, stroke, hospitalization and cost outcomes
Summary (Tell them what you told them) • Atrial Fibrillation involves many patients and it’s growing • It is often progressive, from rare paroxysmal episodes to more persistent or permanent conditions • Antiarrhythmic Drugs and cardioversion should be considered in symptomatic patients, but they are often ineffective and limited by patients’ comorbidities • Although labor intensive and associated with some procedural and periprocedural risks, Radiofrequency Ablation can be a safe and effective treatment for symptomatic AF patients in whom A.A. drugs have failed • The earlier we see these patients, the more likely we are to have successful outcomes
Thank you. Gregg Shander, MD, FACC
STARRII Trial
Tell them what you’re going to tell them • Atrial Fibrillation epidemiology • Natural history • Pharmacologic treatments for AF (Rate vs Rhythm Control) • Catheter Ablation for AF – What does it look like – Trial Data
Problems with AFFIRM Trial • Erroneous conclusion would be never to use A.A. drugs • AFFIRM Trial does not address symptoms in an individual patient • Symptoms are the only absolute reason to use a Rhythm Control strategy – No indication of improved mortality with any rhythm control strategy – No indication of decreased stroke risk. Pt who requires anticoagulation, must still take anticoagulation