ATRIAL FIBRILLATIONDavid W Kabel MD, FACC

September 4, 2013

AF-Scope of the Problem 2.7 million Americans have atrial fibrillation

Numbers are expected to rise in the future Aging population More chronic cardiac conditions Better detection through long term monitoring

Event monitors, pacemakers, implantable monitors

Costs continue to rise Annual cost is $7-10 billion per year and rising

Admissions for AF are up 66% in past 20 years

AF-Prevalence by Decade Overall prevalence-1%

<65 3-5%

<80 10%+

1.5 times higher in men

2 times higher in caucasians

AF-Associated Conditions Cardiac risk factors

Hypertension ASHD and PVD CHF Cardiac surgery (25-30% postop)

Non-cardiac risk factors Family history of AF Diabetes and metabolic syndrome Obstructive sleep apnea Obesity Psychological stress COPD Hyperthyroidism Tall stature Inflammatory conditions (elevated CRP)

Modifiable risk factors Smoking ETOH >3 drinks per day

“Lone” Atrial Fibrillation AF in absence of underlying risk factors

12-20% of all AF patients

45% of AF in younger patients

Classification of AF

AF-History and Physical Exam

Presence and nature of symptoms Clinical type Onset of first attack or date of discovery Frequency, duration, precipitating factors,

and mode of termination Response to any medications previously

given Presence of underlying heart disease or

other reversible conditions (hyperthyroidism, etc)

AF-EKG Confirm presence of AF LVH P wave morphology Pre-excitation Previous MI Left or Right BBB Other atrial arrhythmias Measure PR, QRS, and QT intervals in

conjunction with anti-arrhythmic therapy

AF-Transthoracic Echo Valvular disease LA and RA atrial size LV size and function LVH Right sided pressures (pulmonary

hypertension) LA thrombus(low sensitivity) Pericardial disease

AF-Initial Workup Chest X-ray

Cardiomegaly Pulmonary disease

Blood work Thyroid functions BMP Hepatic profile CRP? CBC

AF-Additional Testing May be indicated in some circumstances Stress testing

If AF is exercise induced To assess rate control

Holter monitor, event monitor If diagnosis is in question To assess rate control

TEE Looking for LAA thrombus To guide cardioversion

EP studies Wide complex tachycardia Pulmonary vein isolation AV node ablation and pacemaker

Sleep study-especially if episodes are mostly nocturnal

AF-Goals of Therapy Rate control

Most important initial strategy Prevention of CHF (tachycardia induced

cardiomyopathy)

Restoration of sinus rhythm (rhythm control) May be initial strategy in some patients

Prevention of thromboembolism(TE)

AF-DC Cardioversion-Indications Class I

Symptoms or signs of ischemia, hypotension, angina or heart failure

Pre-excitation syndrome with extreme tachycardia and hypotension

Symptoms are unacceptable to the patient Class IIa

Part of long term management strategy Patient preference in cases of infrequent episodes of AF

Class III Relatively short intervals between episodes of AF Presence of digitalis toxicity or hypokalemia

Anticoagulation Prior to DCC

Class I Duration >48 hrs or unknown-Oral anticoagulation

(OAC) for 3 weeks before and 4 weeks after DCC Duration >48 hrs and hemodynamically unstable-IV

heparin followed by OAC for 4 weeks. Role of LMWH is uncertain

Duration <48 hrs-DCC without prior OAC, followed byOAC post-procedure depending upon TE risk

Class IIa Duration <48 hrs-OAC prior dependent upon risk TEE guided-Proceed if no LAA thrombus-OAC for 4

weeks post DCC. Limited date on LMWH

AF-Non-Pharmacological Therapies

AV node ablation with pacemaker Indicated in persistent or permanent AF when ventricular

rate cannot be controlled medically or patient is intolerant to rate control medications

Cryoablation of AV node Patient becomes pacemaker dependent

Pulmonary vein isolation-cryoablation Right sided approach across atrial septum to LA. 4 pulmonary veins are identified and cryoablation occurs

in circular pattern around pulmonary vein orifices Rare complication of PV stenosis leading to PHT Initial success rate of 80-90% Repeat PVI common

AF-Non-Pharmacological Therapies

Surgical Maze Procedure

Series of incisions inside the left atrium to redirect and organize electrical impulses -done on cardiopulmonary bypass

Usually done in conjunction with mitral valve surgery or other cardiac surgeries

May be done as stand alone procedure in intractable cases who are highly symptomatic

AF-Prevention of Thromboembolism(TE)

Risk Stratification is key to decision making

Must weigh risk of bleeding into the calculation

Newer anticoagulants appear “non-inferior” to warfarin for prevention of TE

“Non-valvular” AF means absence of rheumatic mitral valve disease of mechanical prosthesis

AF-Prevention of Thromboembolism

Estimates are that only 50-60% of AF patients at risk for TE are on OAC

Reasons cited include risk of bleeding and risk of falls.

Patients at highest risk of bleeding and falls are also at highest risk of TE

Swedish AF Cohort Study 182,000 patients through national

registry

Compared risk of ischemic stroke without OAC vs risk of intracranial hemorrhage while taking OAC

Used CHADS-VASC and HAS-BLED scoring systems

Swedish AF Cohort Study

AF-Swedish AF Cohort Study

AF-Donze, etal AJM-Risk of Falls and Major Bleeds in Patients on OAC

AF-Donze, etal

AF-Donze, etal

AF-Donze, etal

ATRIA Study Anticoagulation and Risk Factors in AF

Cohort

Kaiser Permanente of Northern California database

13,559 adults with AF followed a mean of 6 years

Followed patients taking and not taking OAC

ATRIA-Risk-Benefit Calculation

ATRIA-Benefit by CHADS2 Score

Implications of ATRIA Benefits of OAC far outweigh risks in high risk

populations, even when intracranial hemorrhage is weighted a higher risk

More weight can be assigned to age Vascular disease and ischemic heart disease do

not appear to increase TE risk in AF Renal disease and proteinuria are risk factors

for TE ATRIA score may be better at predicting both

low risk patients and those at highest risk of severe stroke than CHADS2 and CHADS-VASC

AF-Conclusions The incidence of AF is rising exponentially

due to an aging population and improved prognosis in patients with cardiovascular disease

AF is multifactoral Prevention of AF depends upon aggressive

management of risk factors such as hypertension

Strategies of rate vs rhythm control depend upon individual patient characteristics

AF-Conclusions There are several anti-arrhythmic drugs

available, all of which have issues of effectiveness and side effects which limit their usefulness

Non-pharmacologic therapies are gaining in popularity and becoming more effective

AF is associated with high medical costs in both inpatient and outpatient settings

AF-Conclusions A large number of AF patients are at low

risk for TE and should be treated with ASA or nothing

OAC is under-utilized in the group of patients at highest risk for ischemic stroke, namely the elderly

Risk for falls is not a contraindication to OAC