MANAGEMENT OF
ATRIAL FIBRILLATION
Mary N. Healy, MS, ARNP-BC
Heart & Vascular Center of Sarasota
OBJECTIVES
1. Define the difference between paroxysmal and
2.
3.
4.
5.
persistent Atrial Fibrillation
State the CVA risk per year of a 68 yr old female with
hypertension that presents with new onset paroxysmal
atrial fibrillation
Discuss two reasons to pursue rhythm control over rate
control
Name 2 patient conditions in which warfarin is the only
safe consideration for thromboembolic events in AF
Idenitify one drug that can be used for pharmacologic
cardioversion to restore normal sinus rhythm
Pearls of AF Management
• Address underlying triggers
• Hyperthyroidism, hypertension, obesity, alcohol, OSA, U/LRI
• Everyone needs rate control (to improve symptoms &
prevent tachycardia related cardiomyopathy)
• <80 at rest and <110 most simple activity-assess with Holter
monitor
• Use beta blocker if pt has CHF or CAD
• Use non-dihydropyridine CCB in those with COPD or asthma
• If more rate control needed, add digoxin
• Rate vs Rhythm control
• AFFIRM and RACE trials showed that mortality rates were slightly
better with rate control. However the exceptions are: <65, those
with CHF, those with persistent symptoms despite rate control
Pearls of AF Management
• Drugs or Ablation for Rhythm Control
• Opportunity for shared decision-making. Ablation more successful,
but is associated with more risk. If drugs not successful, follow with
ablation.
• Amiodarone has benefit of both rate and rhythm control, but has
serious potential side effects
• When to Anticoagulate and What Drug to Use
• Make life easy, download an app to your phone to figure
CHA2DS2VASc & HAS-BLED score
https://itunes.apple.com/us/app/cardiocalculator/id955390696?mt=8
• CHA2DS2VASc of 2 or more and HAS-BLED score of < or = 3
warrant anticoagulation with warfarin or a novel oral anticoagulant
APP for Thromboembolic Risk
Pearls of AF Management
• Use warfarin in those with valve replacement, mitral stenosis, end-
stage kidney disease or on dialysis
• If you use a novel anti-coagulant with chronic kidney disease, the
dose needs to be reduced
• In the elderly with the novel agents, periodically re-evaluate renal
function do determine if dosage changes should be made
• Dual antiplatelet therapy (aspirin + clopidogrel) is no longer
recommended due to risk of bleeding
INTRODUCTION TO AF
Incidence/Scope of the Problem
• Mechanisms causing AF are multi-factoral,
making it a complex and many times difficult for
practitioners to manage.
• Symptoms range from non-existent to severe.
• Frequent hospitalizations, thromboembolic
events, hemodynamic disruptions result in
significant morbidity and mortality.
Scope of Problem
Stroke/CHF/Dementia Risk
• 5 fold increase risk of stroke, and stroke risk
increases with age
• AF related stroke is likely to be more severe than
non-AF stroke
• 3 fold risk of CHF
• 2 fold increased risk of dementia as well as death
Scope of Problem
Costs
• Hospitalizations with AF as the primary diagnosis
accounts for >467K admits in the US.
• >100K deaths/year
• Pts. with AF are twice as likely to be hospitalized
& 3 times more likely to have multiple
hospitalizations
• Treating pts. with AF adds ~$26 billion to the US
healthcare bill annually.
• Affects 6.1 million American adults and is
expected to double in the next 25 years.
Definition of Atrial Fibrillation
• AF is a supraventricular tachyarrhythmia with
uncoordinated and ineffective atrial contraction
• Characterized by;
• Irregular R-R intervals
• Absence of P waves
• Irregular atrial activity (fibrillation waves)
Mechanisms of Atrial Fibrillation
Patient Assessment
Triggers of AF
Risk Factors
• Hyperthyroid
• Increasing Age
• ETOH use
• European ancestry
• Recent Pulm. Infection
• FH/Genetics
• OSA
• Smoking
• Immediate post-surgery
• Inordinate Stress
• Electrolyte Imbalance
• LVH/LAE/Mitral Valve Dis.
• CHF
• DM
• MI
• HTN
• Obesity
Patient Assessment
Chief Complaint
• May be asymptomatic
•
•
•
•
•
•
especially if >65 yr.
Fatigue
Palpitations
SOB
Dizziness
Syncope
Frequent urination
Physical Findings
• Irregular pulse
• Irregular JVP
• Variation of intensity of S1
• May also find:
• CHF symptoms
• Valvular murmur of MR or
MS
Suggested Treatment Algorithm
REDUCING THROMBOTIC
RISK
Priority #1 in AF/Reduce Embolic Risk
• Therapy based on
• For pts with artificial
shared decision making
• Base on risk of TE risk
regardless of pattern
(paroxysmal, permanent,
etc)
• In non-valvular AF,
CHA2DS2-VASc is
recommended
assessment of CVA risk
heart valves, warfarin is
recommended.
• Balancing the Risks and
Benefits
• Non-valvular AF increases
CVA risk x5.
• AF in presence of mitral
stenosis, increases CVA
risk x 20 over those in NSR
90% of strokes from AF are caused by a
clot in the left atrial appendage
Antithrombotic Options
• Prevent strokes and systemic emboli in part by reducing
the formation of platelet rich or thrombotic clots in the LA
or LA appendage
• Clinical Trials have looked at Warfarin vs aspirin; aspirin
with warfarin or clopidogrel (Plavix®) and aspirin; warfarin
vs. aspirin and clopidogrel; warfarin vs. direct thrombin
inhibitors (dabigatran-Pradaxa®); warfarin vs. Xa
inhibitors (Apixaban-Eliquis® & rivaroxaban-Xarelto®)
Coag Cascade and Antithrombotics
Warfarin
• Vitamin K antagonist (VKA) in use since the 1950’s.
• Works on multiple sites of the coagulation cascade-
Factor IX, VII, X, II
Pros
• Inexpensive, available as generic
• When INR therapeutic, significant risk reduction in stroke risk
Cons
• Narrow therapeutic window
• Increased risk of serious bleeding, including brain
• Interaction with other drugs
• Effects of alterations in diet
• Freq. blood tests- therapeutic range achieved only ~55% of time
Dabigatran
• Direct Thrombin Inhibitor
• 150mg BID superior to warfarin in stroke, systemic
embolism. Hemorrhagic strokes, less, but major bleedsnon inferior to warfarin. Average CHADS score 2.1
• Also available 75mg BID for CrCl 15-30 mL/min-this dose
never studied.
Pros
• No blood testing
• No drug or dietary interaction
Cons
• BID dosing
• High price
Rivaroxaban
• Direct factor Xa inhibitor (excreted by kidneys)
• Studied older pts and mean CHADS score was 3.47
• Non-inferior to warfarin in stroke risk and major bleeding,
but did have less fatal bleeding and less brain bleeds.
• Dose is 20mg daily with evening meal for CrCl>50mL/min
or 15mg for CrCl 30-49mL/min
Pros
• No blood testing
• Once daily dosing (though is with evening meal)
• Minimal drug and no dietary interactions
Cons
• Expensive
Apixaban
• Direct factor Xa inhibitor (eliminated hepatically and highly
protein bound)
• Significantly better than warfarin in reducing strokes (both
ischemic and hemorrhagic), systemic emboli and major
bleed events. Fewer deaths than warfarin
• Average CHADS 2.1, mean age 70
• Dosing-5mg bid unless meet two of the following: age > or
= to 80, weight < or = to 60Kg, serum creatinine
>=1.5mg/dL, then 2.5mg bid
Pros and Cons
•
Similar to the other novel anticoagulants
General considerations in choosing
anticoagulants
• If stable on warfarin
• Reversing warfarin:
and pt is happy with
blood testing, etc, no
need to change
• Medicare pts are
covered if they wish, to
do home monitoring
checks-may increase
the time in therapeutic
range
Aquamephyton (Vitamin
K) usually po, is
available IV, takes
several hours to reverse
FFP infusion, time to
reverse
Anticoag Considerations, cont’d
• If warfarin chosen as
anticoagulant, it will take
AT LEAST 5 days, and
probably longer to
achieve therapeutic INR,
strongly consider using
subq heparin, or
enoxaparin to bridge
until therapeutic
• Pt education required to
counsel on testing, drug
& food interactions
• Novel anticoagulants are
approved in AF for “nonvalvular” AF. Also
approved for other
indications, DVT, PE, but
NOT FOR METAL
VALVES
• Rapid onset and offset
of action so bridging is
usually not needed.
• Strict compliance with
new agents is critical
Role of Antiplatelets
• Limited data on the benefit of aspirin
• In primary prevention of stroke in AF, may reduce risk by 0.8%/yr (#
needed to treat-125)
• For secondary prevention in those with TIA or strokes aspirin
associated with risk reduction of 2.5%/year (# needed to treat-40)
• These data based on meta analysis. In the study that showed the
most benefit, 325mg dose was used
• Aspirin ineffective in preventing strokes in those >75 and did not
prevent severe strokes
• Clopidogrel + aspirin
• Better than aspirin alone, but benefits are tempered by a significant
increase in major bleeding events
• Studies show clear benefit of warfarin over C+A and Eliquis over
C+A
HAS-BLED score for bleeding risk on oral anticoagulation
in atrial fibrillation
Feature
• HTN (Systolic ≥ 160mmHg)
• Abnormal renal function
• Abnormal liver function
• Stroke in past
• Bleeding
• Elderly
• Labile INRs
Score if present
1
1
1
1
1
1
1
• Drugs
• NSAIDS, antiplatelets
• ETOH
1
1
NON-PHARMACOLOGIC
STROKE PREVENTION
Left Atrial Appendage (LAA) Occlusion By:
WATCHMAN Device (Boston Scientific)
Amplatzer cardiac plug (St. Jude)
LAA Occlusion by using LARIAT (SentreHEART)
device that ties off the LAA “epicardial snare”
Requires subxiphoid pericardial approach
Surgical excision of the LAA for pts undergoing
cardiac surgery
Yields inconsistent results
Masoudi FA, Calkins H, Kavinsky C; 2015 ACC/HRS/SCAI Left atrial Appendage Occlusion Device Societal
Overview, JACC 2015;Jun 29
RATE CONTROL
Resting rate < or = to 80, or average awake rate <100
Exercise rate should not exceed >100% of maximum
predicted exercise rate
Rationale for Rate Control
• This is an important strategy as it
• Impacts QOL
• Reduces morbidity
• Decreases potential for developing tachycardia induced
cardiomyopathy
• When selecting which agent(s) to use, must consider
symptoms, hemodynamic status, presence of HF
• Beta blockers, non-dihydropyridine CCB’s, digoxin, amiodarone,
sotalol are the main considerations
• When rapid control of ventricular rate during AF required,
IV meds or electrical CV may be used.
• May increase TE risk in those inadequately anticoagulated
AV Node Ablation as Rate Control
Strategy
• Permanent Pacemaker implantation with subsequent AV
node ablation effectively controls and regularizes
ventricular heart rate and in select patients, improves
symptoms
• Those most likely to benefit are those with symptomatic
AF with RVR that is either non responsive to medications
or the pt is intolerant to the meds
• Usually reserved for the elderly, as it makes one
pacemaker dependent
• Rate control meds no longer needed, but still require
anticoagulation
RHYTHM CONTROL
Rationale for Rhythm Control
• This is a chance for shared decision making with the pt.
• Always treat precipitating or reversible causes first
• All rhythm control options should be considered only
under optimal TE prevention strategies.
• If symptoms not controlled with rate regulation, or pt less
than 65 yrs old, it is reasonable to pursue restoration of
NSR
• Choices include Pharmacologic, Ablation, Electrical
Cardioversion alone or in combination
• Drugs that can convert: Amiodarone (IV/PO), Dofetilide
(PO), Flecainide (PO), Propafenone (PO), Ibutilide (IV)
Drug Selection for Rhythm Control
AF Ablation
• Invasive procedure to isolate the atrial impulses causing
AF and ablating those electrical pathways. Most common
way is using radio frequency ablation, but cryo-ablation is
now also being used.
• Associated with higher risk than antiarrhythmic drugs, but
is generally more effective over the long term.
• Usually recommended for pts with symptomatic
paroxysmal or persistent AF who are refractory or
intolerant to at least 1 antiarrhythmic drug
Electrical Cardioversion
• Recommended for symptomatic AF with RVR that does
not respond promptly to pharmacologic therapies and
contributes to ongoing ischemia, hypotension or CHF
• Ideally, should be anticoagulated for 3 weeks prior, placed
on an antiarrhythmic med, with a TEE to rule out intraatrial clot, cardioversion then performed immediately
following TEE. If clot is seen, CV is not performed.
• If AF is clearly less than 48 hours in duration, CV can be
performed without TEE. Pt. should be anticoagulated
ASAP.
• TE is most likely to occur within 72 hours after CV, can be
as long as 10 days.
References
• Cairns JA, Connolly S, McMurtry S, Stephenson M, Talajic M; CCS
•
•
•
•
Atrial Fibrillation Guidelines Committee. Canadian cardiovascular
society atrial fibrillation guidelines 2010: prevention of stroke and
systemic thromboembolism in atrial fibrillation and flutter. Can J
Cardiol. 2011 Jan-Feb;27(1):74-90.
Prystowsky EN, Padanilam BJ, Fogel, RI. Treatment of Atrial
Fibrillation. JAMA. 2015;314(3):278-288.
Moss JD, Cifu, AS. Management of Anticoagulation in Patients with
Atrial Fibrillation. JAMA. 2015;314(3):291-292.
Chugh, A, Masoudi FA, Calkins H, Davisnsky, C. 2015
ACC/HRS/SCAI Left Atrial Appendage Occlusion Device Societal
Overview. JACC. 2015: June 29.
January, CT, Wann, LS, et al. 2014 AHA/ACC/HRS Guideline for the
Management of Patients With Atrial Fibrillation. JACC. Vol 64, No 21.
e1-79.