ATRIAL FIBRILLATION

Dr SYED RAZA MD,MRCP(UK),CCT(UK),MESC,Dip.Card(UK),FCCP

Consultant Cardiologist

OBJECTIVES

• Introduction• Classification• Burden of the problem• Diagnosis• Management

What is it ?

• Abnormal electrical wavelets originate from left atrium

• Propagating in different directions• Disorganized atrial depolarisation without

effective atrial contraction

DIAGNOSIS

• Pulse palpation• 12 lead ECG• Holter monitoring

• Others• Echocardiogram, CXR• TFT, Electrolytes, Clotting, LFT,CBC

ECG Diagnosis

• On ECG p waves are absent and RR interval is variable.

• f waves 350-600 beats /min.• ventricular response is grossly irregular at

100-160 beats /min. • Rate : No. of R waves x 10 ( 6 sec strip)

Prevalance

• 2.2 Million people in the US• 6.5 cases/1000 examinations • 4% > 60yrs• 8 % > 80 yrs• 25% of individuals aged 40 yrs and older will

develop AF in their life time.

Prevalence of AF in the Renfrew-Paisley study

Cohort of men and women aged 45–64 years (n = 15,406)

Reproduced with permission of the BMJ Publishing Group from Stewart S et al, Heart 2001: 86:516-21

Clinical events (outcomes) affected by AF

Outcome Parameter Relative change in AF patients

1.Death2.Stroke

3.Hospitalisation 4.Quality of life and exercise capacity5.LV function

1.Death rate is doubled2.Stroke risk increases 5 times3.More frequent4.Can be markedly decreased5.Tachycardiomyopathy/heart failure

Terminology Clinical features

Initial event (first detected episode)

Symptomatic Asymptomatic Onset unknown

Rhythm/Rate

Paroxysmal Spontaneous termination <7 days and most often <48 hours

Rhythm Control

Persistent Not self-terminating Lasting >7 days or prior cardioversion

Rhythm or Rate control

Permanent (‘accepted’)

Not terminated Terminated but relapsed No cardioversion attempt

Rate Control

Classification of AF

Etiologies of AF

CARDIAC Hypertensive heart disease Valvular heart disease Ischaemic heart disease Cardiomyopathy Pericarditis Congenital heart disease Post Cardiac surgery

Etiologies of AF contd:

NON CARDIAC 1. Pulmonary : Pneumonia, COPD,PE2. Hyperthyroidism3. Excess catecholamine /sympathetic activity4. Drugs and alcohol5. Significant electrolyte imbalance

LONE ATRIAL FIBRILLATION

• Younger patients < 60• No underlying cause • Usually not much symptoms• Normal heart structure• No associated co-morbidities

Why AF management is important?

• extremely common• Can lead to symptoms• potentially serious consequences:

– embolism– impaired cardiac output– increased mortality

Management of Acute AF (<48 hrs)

• Haemodynamically unstable : hypotension/heart failure/chest pain/syncope

Use DC Cardioversion Haemodynamically stable : Rate control : If significant tachycardia Rhythm control : Flecainide, Propafenone (cl-I)

Amiodarone, Sotalol (cl-III) Anticoagulant : LMWH

Treatment for permanent AF

• Heart Rate control

minimise symptoms associated with excessive heart rates

prevent tachycardia-associated cardiomyopathy

• Anticoagulation

Rhythm control as preferred therapy

– ? First episode afib– Reversible cause (alcohol)– Symptomatic patient despite rate control– Patient unable to take anticoagulant (falls, bleeding,

noncompliance)– CHF precipitated or worsened by afib– ? Young afib patient (to avoid chronic electrical and

anatomic remodeling that occurs with afib)

Rate control as preferred therapy

– Age > 65, less symptomatic, hypertension– Recurrent afib– Previous antiarrhythmic drug failure – Unlikely to maintain sinus rhythm (enlarged LA)

Cardioversion

• Cardioversion is performed as part of a rhythm-control treatment strategy

• There are two types of cardioversion: electrical (ECV) and pharmacological (PCV)

• Cardioversion of AF is associated with increased risk of stroke in the absence of antithrombotic therapy.

96%96% 96% 96%

87% 89%87% 89%

76% 76% 79% 79% p = 0.058p = 0.058

NO Difference :NO Difference : death, disabling stroke, major bleed, death, disabling stroke, major bleed, or cardiac arrestor cardiac arrest

Sinus rhythmSinus rhythm maintained in only 63% of rhythm maintained in only 63% of rhythm control group control group

AFFIRM : 5 Year Outcomes

NEJM 2002;347:1825NEJM 2002;347:1825

Survival Survival Rhythm Control Rate Control Rhythm Control Rate Control

1 year1 year

3 year 3 year

5 year5 year

Rate Control Options

• Beta blocker• Calcium channel blocker

• Verapamil, diltiazem

. Digoxin

• AV junction ablation plus pacemaker

STROKE RISK

Without AF < 60 yrs : 0.5% > 80 yrs : 3 yrs

With AF < 60 yrs : 3% > 80 yrs : 30%

Lip Y, et al. Chest 2010, 137(2):263

How do we determine stroke risk ?

– 0 points – low risk (1.2-3.0 strokes per 100 patient years)

– 1-2 points – moderate risk (2.8-4.0 strokes per 100 patient years)

– > 3 points – high risk (5.9-18.2 strokes per 100 patient years)

Atrial fibrillation 2009Target INR 2-3

ACC AHA HRS Afib Focused Update(Dabigatran), March 2011

• Non-inferior to warfarin re thromboembolism (afib)• Caution when CrCl < 30ml/min• Increased dabigatran levels with amiodarone, verapamil• Half life 12-17 hours• No reversal re hemorrhage

– dialysis

• Coagulation testing ??? aPTT, dilute thrombin time

Who should remain on warfarin?

• Patient already receiving warfarin and stable whose INR is easy to control

• If dabigatran, rivaroxaban, apixaban not available• Cost• If patient not likely to comply with twice daily dosing

(Dabigatran, Apixaban)• Chronic kidney disease (GFR < 30 ml/min)

Bleeding Risk

• Assessment of bleeding risk should be part of the clinical assessment of AF patients prior to starting anticoagulation

• Antithrombotic benefits and potential bleeding risks of long-term coagulation should be explained and discussed with the patient

• Aim for a target INR of between 2.0 and 3.0• Forms of monitoring include point of care or

near patient testing and patient self-monitoring

From Hart RG, et al. Stroke. 2005;36:1588

RF ABLATION THERAPY

Triggering eventsSubstrate for initiation

Substrate for perpetuation

When to consider ablation?

• Antiarrhythmic therapy ineffective• Antiarrhythmic therapy not tolerated• Symptomatic afib

Others in whom ablation may be a first strategy

• Patient very symptomatic in AF and refuses antiarrhythmic drug therapy

• Young patient whose only effective antiarrhythmic drug is amiodarone

• Patient with significant bradycardia for whom antiarrhythmic drug therapy will require pacemaker

Summary

• AF is the commonest arrhythmia• High prevalence • Stroke is one of the most dreadful

complications .• Different management strategies,