6. Afib/Atrial Flutter

Atrial rate of A-fib

350-450 BPM

MC sustained arrhythmia

A-fib

Risk factors for A-fib

Frequency increases w/ age

A-fib

Continuous. rapid firing of multiple automaticity foci in atria

Appearance of A-fib on EKG

- NO normal P waves

- Wavy baseline

- Irregular ventricular rhythm

MCC of A-fib

- Chronic HTN

- Valve disease

- Cardiomyopathy

- PE

Other causes of A-fib

- Acute heavy alcohol use (Holiday Heart)

- Hyperthyroidism

- Obstructive sleep apnea

Workup for NEW onset of A-fib

- Electrolytes

- TSH

- Echo

Risks/Complications for A-fib

- Thromboembolism (MC in LA → emboli in brain) causing stroke

- Acute/chronic HF

Goal of rate control

Control HR acute/chronic

Indications for use of rate control

Rhythm control methods contraindicated/ineffective

Beta blockers for rate control

Metoprolol, atenolol, carvedilol

Calcium channel blockers for rate control

Diltiazem, verapamil

Function of BB on heart

Increase refractory period of AV node → decreased HR

Function of CCB on heart

Block Ca channels at SA and AV node

Mainstay treatment for short & long-term rate control

BB and/or CCB

Common side effects of BB and/or CCB for acute A-fib management

Hypotension

Function of digoxin on heart

Increase refractory period of AV node with no effect on BP

HR goal for acute A-fib

Resting <100 BPM

Long-term goal of rate control for management of chronic A-fib

Prevent ventricular damage from chronic tachycardia

Treatment for chronic rate control of A-fib (+ special situations)

BB or CCB (or combo)

HF or CAD: Carvedilol or long-acting metoprolol

HR goal for chronic A-fib

Rest: <80 BPM

Light exertion: <100 BPM

Chronic management of A-fib if medications are ineffective

AV ablation

Permanent pacemaker

Goal of rhythm control

Restore and maintain NSR

Indications for use of rhythm control

- Initial therapy for chronic control

- Symptomatic despite rate control efforts

Options for rhythm control

- Anti-arrhythmic meds

- Electrical cardioversion

Reminders prior rhythm control management

A-fib >48 → transesophageal echo to rule out LA clot PRIOR TO pharmacological/electrical cardioversion

Adverse effects of antiarrhythmics

Prolonged QT

Initiation of antiarrhythmics therapy for rhythm control

Hospital monitor of EKG for first 2 days

Contraindicatoins of antiarrhythmics

Cardiomyopathy

Antiarrhythmic with special characteristics

Amiodarone - can be used w/ HF, CAD, ESRD

Adverse effects of amiodarone

- Lung fibrosis

- Hypo/thyroid

- Liver toxicity

Electrical cardioversion for rhythm control (+ indications/management)

- Electrical shock to reset rhythm and allow sinus node to regain control

- Recent/known onset

- 4 weeks anticoag post-procedure

Surgical options for rhythm control

- AV node ablation

- A-fib catheter ablation

- Maze procedure

AV node ablation (+ indications)

A-fib catheter ablation (+ indications)

Maze procedure

Open heart surgery to make lesions (in maze-like pattern) → disrupts signal propagation

Mini-Maze procedure

Thorascopic

Indications for prevention of thromboembolic events

Anticoagulations if CHA2DS2VASC score 2 or higher

Antigoagulation with mechanical heart valve

Warfarin

CHA2DS2VASC score is used to determine...

Determines estimated annual stroke risk

CHA2DS2VASC score criteria

CHF - 1

HTN - 1

A2 - Age ≥ 75 - 2

Diabetes - 1

S2 - Stroke - 2

Vascular disease - 1

Age 65 to 74 - 1

Sex female - 1

Parenteral anticoagulant

Heparin

Unfractionated: IV

Low molecular weight: SubQ

Anticoagulant: Vitamin K antagonist

Warfarin (Coumadin)

Anticoagulant: Direct thrombin inhibitor

Dabigatran (Pradaxa)

Anticoagulant: Factor Xa inhibitor

Rivaroxaban (Xarelto)

Apixaban (Eliquis)

Edoxaban (Savaysa)

Unfractionated heparin

- Rapid acting, short half-life

- aPTT to regulate dose

- Used as "bridge"

Cautions with unfractionated heparin

- Heparin-induced thrombocytopenia

- Hepatically cleared

Low molecular weight heparin

- Enoxaparin (Lovenox)

- Dosed by weight

- SubQ → can be self administered

Cautions with low molecular weight heparin

- Renally excreted

- Not ideal w/ obesity

Warfarin (PO) for A-fib

- Dosed with INR with goal 2-3

- Correct w/ vitamin K

- Hepatically cleared

Patient education for Warfarin (PO) for A-fib

Interacts w/ high vitamin K foods (leafy green, ETOH, herbal)

Novel oral anticoag/direct oral anticoag (NOAC/DOAC)

- Dosed by weight and GFR (levels NOT monitored)

- Used instead of Warfarin due to lower risk of major bleeding & intracranial bleeding (most cases)

- Renally cleared (assess annually; dose adjusted for renal insufficiency)

Types of DOACs

Dabigatran

Rivaroxaban

Apixaban

Transitioning from warfarin to DOAC

Start DOAC when INR down to 2

Stopping DOAC w/ low-moderate bleeding risk (+ consideration)

Stop 24-48 hours before (longer w/ impaired renal)

Stopping DOAC w/ major surgery (+ consideration)

Stop 50-60 hours before (longer w/ impaired renal)

Dabigatran reversal agent

Idarucizumab

Reversal of Factor Xa inhibitor AC

Andexanet alfa

HAS-BLED score determines...

1 year major bleeding risk on AC (review annually)

High risk: ≥3

HAS-BLED score

1 point for each:

HTN

Abnormal renal

Abnormal hepatic

Stroke

Bleeding hx

Labile INR

Age >65

Drugs/EtOH

Management of high stroke risk AND high risk of bleeding

- LA appendage ligation

- LA occlusion device

Management of A-flutter

Rate control (BB or CCB or both)

Cardioversion

Management of chronic/recurrent A-flutter

Anticoagulation

Catheter ablation A-fib vs A-flutter

High success rates with A-flutter