Is cardioversion old hat? What is new in interventional treatment of AF symptoms? Joseph de Bono Consultant Electrophysiologist University Hospitals Birmingham
Atrial Fibrillation (AF) Affects 2% of the population Easily diagnosed 25% of 40 year olds will go on to suffer from AF Increases the risk of stroke 5x 20% of all strokes are due to AF
Symptoms from Atrial Fibrillation Irregular, often rapid ventricular rate Decreased cardiac output Symptoms of palpitations, fatigue, dyspnoea, dizziness and chest pain Loss of atrial contractility Decreased cardiac output Symptoms of fatigue and dyspnoea Risk of atrial thrombus formation and thromboembolism Death - AFib alone increases risk of death by 50-90% (Framingham)
Atrial fibrillation Paroxysmal Atrial fibrillation Self terminating (<7 days) Persistent Atrial Fibrillation Continuous > 7days or requires Cardioversion Long standing Persistent Atrial Fibrillation Continuous for > 1 year
What is important in AF management? 1.Prevent Strokes 2.Treat Symptoms
Traditional symptomatic treatments for Atrial fibrillation DC Cardioversion Pills Ablate and Pace
Cardioversion Cheap Easy to do High initial success rates (>90%) Not suitable for paroxysmal AFib Requires 1 month s anticoagulation before, and at least 3 months after
Cumulative mortality (%) Does rhythm control matter? 30 P=ns 25 20 15 10 Rhythm control Rate control 5 0 0 1 2 3 4 5 The AFFIRM Study N Engl J Med 2002; 347:1825-1833
Percent in Sinus Rhythm The problem with cardioversion? 100 90 80 70 60 Amiodarone Diltiazem Control 50 40 30 0 10 20 30 40 50 Long term success from cardioversion extremely poor Manios et al. Cardiovascular Drugs and Therapy 17 31 39 2003
Mechanisms of Atrial Fibrillation Keith & Flack, 1907 Cardioversion only resets the system Triggers: Pulmonary Vein SVC No effect on Triggers or Substrate Haissaguerre, NEJM, 1998 Normal Atrium Fibrosed atrium Substrate: Left atrial enlargement Fibrosis Rotors Electrical changes
Relative importance Paroxysmal AFib Long Standing Persistent AFib Triggers Substrate
The problem with drugs Amiodarone
The problem with drugs Sotalol Chong D W S et al. BMJ Case Reports 2009;2009:bcr.01.2009.1426
AFFIRM Revisited 47% Sinus rhythm is associated with reduced mortality The AFFIRM investigators. Circulation 2004;109:1509-1513
Does Rhythm control improve survival 47% 49% Sinus rhythm is associated with reduced mortality Antiarrythmic drugs are associated with increased mortality The AFFIRM investigators. Circulation 2004;109:1509-1513
When does Cardioversion work? 1 st Presentation When there is an acute trigger that has been reversed
AF is triggered from the pulmonary veins (90%) Electrical isolation of the pulmonary veins will stop Paroxysmal AF Haissaguerre et al NEJM 1999 A break through in Atrial fibrillation
How does it work? Ablation of Paroxysmal AF Keith & Flack, 1907 Cabrera, Circulation, 2002 Muscle sleeves in pulmonary veins act as triggers
Freedom from AF Ablation gives excellent symptom relief in paroxysmal AF? 100 80 60 Ablation Anti-arrhythmic drugs 40 20 Logrank p<0.0001 0 0 100 200 Follow-up (days) 300 The A4 Study Circulation. 2008;118:2498-2505.)
Maximum Workload (METS) Exercise Capacity 60 Mean SF-36 Mental Wellbeing Ablation (n=53) 55 10 Drug Treatment (n=59) 50 P<0.01 9 45 40 Baseline Day 91 Day 180 8 60 SF-36 Physical wellbeing 7 P<0.01 55 50 P<0.01 6 Baseline End of Study 45 40 Baseline Day 91 Day 180 Quality of Life
The Modern Approach Wide Area Circumferential Ablation
Catheter Ablation of Persistent AF Isolate triggers Pulmonary vein isolation (WACA) Ablate Substrate Lines Cavotricuspid isthmus Roof Mitral Isthmus Complex fractionated electrograms
Additional lesions for persistent AF- Roof line PA view (Carto Map) Superior view (NavX Map) Prevents re-entry between the pulmonary veins
Additional lesions for persistent AF- Mitral Isthmus line Prevents re-entry around the Mitral Isthmus
Mitral Isthmus Line Difficult to complete Mitral isthmus is thick Coronary sinus acts as a Heat sink Attack from both sides Mitral Isthmus Coronary Sinus Endocardial Epicardial
Additional lesions for persistent AF- CFAE ablation 58 ms 174 ms CFAE= Complex fractionated atrial electrograms ROTORS Areas of high frequency complex signals Act as Drivers for Atrial Fibrillation
CFAE mapping Atrial activity varies within the left atrium
Success ECG I II Left Atrial III Appendage avf Coronary V1 Sinus V6 Ablation Termination to sinus rhythm with ablation
Who should we ablate? SYMPTOMATIC AF Overall success rate? Often need more than one ablation Predictors of success?
Freedom from arrhythmia Does it work? The STAR AF study 100% p=0.03 80% 60% 40% p=0.14 Pulmonary vein isolation + CFAE Pulmonary vein isolation alone 20% 0% Paroxysmal Persistent AF Less than 1 year Success rate much better with modern techniques (CFAE) No difference between PAF and Persistent (<1 year)
Freedom from AF/AFl/Atach Does it work? The STAR AF study 100% p=0.001 80% 60% 40% AF ablation is very successful for patients with Continuous AF for less PVI + than CFE 1 year PVI 20% 0% 0 1 2 3 4 5 6 7 8 9 10 11 12 Months since last ablation Persistent Atrial Fibrillation after 2 procedures
Freedom from Recurrence (%) Ablation even works in Long Standing Persistent AF 100 90 80 70 60 50 40 30 20 10 0 Duration of Continuous AF < or = 21 months > 21 months P = 0.002 Hazard Ratio =0.13 0 5 10 15 20 25 30 Time since Procedure (months) Matsuo et al. J Am Coll Cardiol 2009;54:788
Are there any contraindications to ablation persistent AF Asymptomatic Very long standing continuous AF (>5 years) Some structural heart disease Hypertrophic cardiomyopathy Very large left atrium Unable to take warfarin IVC obstruction Some ASD repairs
Ablation is not risk free Fatal atrio-oesophageal fistula following AF ablation
Ablation Risks 1/1000 death 1/200 Stroke 3-5% major complication No known mortality benefit 50% patients need two procedure No evidence it removes the need for anticoagulation
Conclusion Cardioversion only indicated at first presentation or to assess symptoms Ablation is a extremely effective in symptomatic patients We can get excellent results even in less good patients May need multiple procedures