Atrial fibrillation resident survival guide

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Hilda Mahmoudi M.D., M.P.H.^[2]; Priyamvada Singh, M.D. [3]

Definitions

Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia, characterized by uncoordinated atrial activation and improper atrio-ventricular mechanical function. This classification is for pri af

• Paroxysmal - recurrent, transient, last less than 7 days,
• Persistent - last more than 7 days
• Permanent - lasting a long period, where in attempted cardioversion has failed or shows no improvement.
• Lone Afib - patients > 60 years, without any cardiopulmonary disease

recurrent - after 2 or more episodes af is considered recurrent.

Secondary af are classified differently.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Congestive heart failure
• Dehydration
• Electrolyte disturbance
• Hypothermia
• Hypoxia
• Myocardial infarction
• Myocarditis
• Pericarditis
• Pheochromocytoma
• Pulmonary embolism
• Uremic pericarditis

Common Causes

• Coronary artery disease
• Hypertensive heart disease
• Rheumatic heart disease

Management

Characterize the symptoms: ❑ Asymptomatic ❑ Palpitations ❑ Dyspnea ❑ Fatigue ❑ Chest discomfort ❑ Lightheadedness ❑ Syncope Characterize the timing of the symptoms: ❑ Onset ❑ Duration ❑ Frequency

Identify possible triggers: ❑ Infection ❑ Caffeine ❑ Alcohol ❑ Nicotine ❑ Recreational drugs ❑ Hypovolemia ❑ Hyperthyroidism Hypoxia Acidosis ❑ Hypokalemia Hyperkalemia Hypoglycemia ❑ Hypothermia Toxins Cardiac tamponade ❑ Pumonary embolism Coronary thrombosis Trauma

❑ Examine the patient ❑ Order an EKG

Newly Discovered Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with newly discovered atrial fibrillation:

Newly discovered AF

Paroxysmal

Persistent

❑ Look for the presence of one of these severe symptoms: ❑ Hypotension ❑ Heart failure ❑ Angina pectoris Severe symptoms absent: ❑ No therapy needed Severe symptoms present: ❑ Attempt direct-current cardioversion

Anticoagulation & heart rate control: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy ❑ Control heart rate as an initial method to terminate AF ❑ Click here for recommended pharmacological agents used for rate control

Anticoagulation: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy ❑ Recommended in all cases except lone AF (I A) ❑ Measure INR weekly initially, then monthly when stable (I A) ❑ Reassess need for anticoagulation at periodic intervals (IIa C)

Rhythm control: ❑ Consider antiarrythmic therapy for maintenance of sinus rhythm Click here for drugs & dosages used for rhythm control

Cardioversion: ❑ Attempt cardioversion ❑ Click here for drugs and doses used for pharmacological cardioversion ❑ If patient hemodynamically unstable or tachycardic attempt electric cardioversion ❑ If pharmacological cardioversion fails attempt electric cardioversion

❑ Do not treat with long term antiarrythmic therapy, unless indicated.

ADD indicates antiarrhythmic drugs
*See figure 5
Algorithm based on the 2011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Recurrent Paroxysmal Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with recurrent paroxysmal atrial fibrillation:

Recurrent paroxysmal AF

Minimal or no symptoms

Disabling symptoms in AF

Anticoagulation & heart rate control: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy ❑ Control heart rate as an initial method to terminate AF ❑ Click here for recommended pharmacological agents used for rate control

Anticoagulation & heart rate control: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy ❑ Control heart rate as an initial method to terminate AF ❑ Click here for recommended pharmacological agents used for rate control

❑ Long term therapy for prevention of AF not needed

Rhythm control: ❑ Consider antiarrythmic therapy for maintenance of sinus rhythm Click here for drugs & dosages used for rhythm control

❑ Consider AF ablation if antiarrhythmic drug treatment fails

*See figure 5
Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Recurrent Persistent Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with recurrent persistent atrial fibrillation:

Recurrent persistent AF

Minimal or no symptoms

Disabling symptoms in AF

Anticoagulation and rate control as needed

Anticoagulation and rate control

Antiarrhythmic drug therapy*

Electrical cardioversion as needed

Continue anticoagulation as needed and therapy to maintain sinus rhythm*

Consider ablation for severely symptomatic recurrent AF after failure of greater than or equal to 1 ADD plus rate control

ADD indicates antiarrhythmic drugs
*See figure 5. Initiate drug therapy before cardioversion to reduce the likelihood of early recurrence of AF.
Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Permanent Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with permanent atrial fibrillation:

Permanent AF

Anticoagulation and rate control* as needed

*See figure 5
Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Antiarrhythmic Drug Therapy in Atrial Fibrillation

Shown below is an algorithm depicting the antiarrhythmic drug therapy for maintain sinus rhythm in patients with recurrent paroxysmal or persistent atrial fibrillation:

Maintenance of sinus rhythm

No (or minimal) heart disease

Hypertension

Coronary artery disease

Heart failure

Dronedarone Flecainide Propafenone Sotalol

Substantial LVH

Dronedarone Dofetilide Sotalol

Amiodarone Dofetilide

Amiodarone Dofetilide

Catheter ablation

No

Yes

Amiodarone

Catheter ablation

Catheter ablation

Dronedarone Flecainide Propafenone Sotalol

Amiodarone

Catheter ablation

Amiodarone Dofetilide

Catheter ablation

Drugs are listed alphabetically and not in order of suggested use.
The seriousness of heart disease progresses from left to right, and selection of therapy in patients with multiple conditions depends on the most serious condition present.
LVH indicates left ventricular hypertrophy.
Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Following table summarizes the list of most commonly used drugs and their dosages for maintenance of sinus rhythm:

Drug	Dose
Amiodarone	100 to 400 mg
Disopyramide	400 to 750 mg
Dofetilide	5000 to 1000 mcg
Flecainide	200 to 300 mg
Procainamide	1000 to 4000 mg
Propafenone	450 to 900 mg
Quinidine	600 to 1500 mg
Sotalol	160 to 320 mg

Pharmacological Cardioversion

Cardioversion upto7 Days

Drug	Dosage
Agents with proven efficacy
Dofetilide (I A)	Creatinine clearance(ml/min) Dose (mg) >60 500 40 to 60 250 20 to 40 125 <20 Contraindicated
Flecainide (I A)	Oral: 200 to 300 mg Intravenous: 1.5 to 3.0 mg/kg over 10 to 20 min
Ibutilide (I A)	1 mg over 10 min; repeat 1 mg when necessary
Propafenone (I A)	Oral: 600 mg Intravenous: 1.5 to 2.0 mg/kg over 10 to 20 min
Amiodarone (IIa A)	Oral: Inpatient: 1.2 to 1.8 g per day in divided dose until 10 g total then 200 to 400 mg per day maintenance or 30 mg/kg as single dose Outpatient: 600 to 800 mg per day divided dose until 10 g total then 200 to 400 mg per day maintenance. Intravenous: 5 to 7 mg/kg over 30 to 60 min then 1.2 to 1.8 g per day continuous IV or in divided oral doses until 10 g total then 200 to 400 mg per day maintenance.

Cardioversion after 7 Days

Drug	Dosage
Dofetilide (I A)	Creatinine clearance(ml/min) Dose (mg) >60 500 40 to 60 250 20 to 40 125 <20 Contraindicated
Amiodarone (IIa A)	Oral: Inpatient: 1.2 to 1.8 g per day in divided dose until 10 g total then 200 to 400 mg per day maintenance or 30 mg/kg as single dose Outpatient: 600 to 800 mg per day divided dose until 10 g total then 200 to 400 mg per day maintenance. Intravenous: 5 to 7 mg/kg over 30 to 60 min then 1.2 to 1.8 g per day continuous IV or in divided oral doses until 10 g total then 200 to 400 mg per day maintenance.
Ibutilide (IIa A)	1 mg over 10 min; repeat 1 mg when necessary

Drugs which enhance the efficacy of cardioversion when given prior to the procedure: (Level of recommendation: IIa B)

• Amiodarone
• Flecainide
• Ibutilide
• Propafenone
• Sotalol

Risk Factors for Stroke and Recommended Antithrombotic Therapy

Low Risk Factors	Moderate Risk Factors	High Risk Factors
Female gender	Age ≥ 75 years	Previous stroke, TIA or embolism
Age 65-74 years	Hypertension	Mitral stenosis
Coronary artery disease	Heart failure	Prosthetic heart valve
Thyrotoxicosis	LV ejection fraction ≤ 35%	-
-	Diabetes mellitus	-

Risk Category	Recommended Therapy
No risk factors	Aspirin, 81-325 mg daily
1 Moderate risk factor	Aspirin, 81-325 mg daily or Warfarin (INR 2.0 to 3.0, target 2.5)
Any high risk factor or more than 1 moderate risk factor	Warfarin (INR 2.0 to 3.0, target 2.5)*

Pharmacological Agents for Heart Rate Control

Drug	Class/LOE Recommendations	Loading Dose	Maintenance Dose
Acute Setting
Heart rate control in patients without accessory pathway
Esmolol	I C	500 mcg/kg IV over 1 min	60 to 200 mcg/kg/min IV
Propanolol	I C	0.15 mg/kg IV	NA
Metoprolol	I C	2.5 to 5 mg IV bolus over 2 min; up to 3 doses	NA
Diltiazem	I B	0.25 mg/kg IV over 2 min	5 to 15 mg/h IV
Verampil	I B	0.075 to 0.15 mg/kg IV over 2 min	NA
Heart Rate Control in patients with accessory pathway
Amiodarone	IIa C	150 mg over 10 min	0.5 to 1 mg/min IV
Heart Rate Control in patients with heart failure and without accessory pathway
Digoxin	I B	0.25 mg IV each 2 h, up to 1.5 mg	0.125 to 0.375 mg daily IV or orally
Amiodarone	IIa C	150 mg over 10 min	0.5 to 1 mg/min IV
Non-Acute Setting and Chronic Maintenance Therapy
Heart rate control
Metoprolol	I C	Same as maintenance dose	25 to 100 mg twice a day, orally
Propanolol	I C	Same as maintenance dose	80 to 240 mg daily in divided doses, orally
Verampil	I B	Same as maintenance dose	120 to 360 mg daily in divided doses; slow release available, orally
Diltiazem	I B	Same as maintenance dose	120 to 360 mg daily in divided doses; slow release available, orally
Heart Rate Control in patients with heart failure and without accessory pathway
Digoxin	I C	0.5 mg by mouth daily	0.125 to 0.375 mg daily, orally
Amiodarone	IIb C	800 mg daily for 1 wk, orally 600 mg daily for 1 wk, orally 400 mg daily for 4 to 6 wk, orally	200 mg daily, orally

Do's

Therapeutic agents for Atrial fibrillation

• No mortality benefit is evident from rhythm control over rate control.
• Rate control with beta blockers (metoprolol/lopressor, atenolol/tenormin) or non-dihydropyridine calcium channel blockers (diltiazem/cardizem, verapamil)is recommended in older patients with chronic AF or unknown duration. Digoxin can be used as a second line drug.
• For young symptomatic AF patients rhythm control is preferred over rate control. Rhythm control can be achieved by medications, synchronized cardioversion or both. If both these options fail, catheter based ablation is an option.
• Sotalol and Dofetelide - monitor QTc interval for prolongation for 48 hrs post initiation. QTc >= 500 or 15% above baseline may increase the risk of Torsades. Check daily EKG or EKG 2 hours post the drug dose.
• Amiodarone can cause bradycardia, hepatotoxicity, throtoxicity, pulmonary fibrosis, and retinopathy.
• Flecanide should be used with beta blockers as it may increases the risk of rapid AV nodal conduction. It also increases digoxin levels
• Hemodynamic stability is first priority, rate or rhythm control 2nd.
• Hypotension could be rate related so treatment should not be avoided.

Cardioversion

• Emergent cardioversion for hemodynamically unstable AF.
• If drug therapy fails, cardioversion with 100 joules of electricity is recomended.
• Prior to an elective cardioversion in patients who have been in AF > 48hrs or unknown duration, either a negative TEE or 3-4 weeks of anticoagulation is recommended.
• Post cardioversion 4 weeks of anticoagulation is recommended.

Anticoagulation for atrial fibrillation

• • CHADS2 score
    • Congestive heart failure - 1
    • Hypertension -1
    • Age > 75 -1
    • Diabetes Mellitus -1
    • Stroke or TIA - 2
  • Score > 2 anticoagulate
  • Score < 2 Aspirin may be sufficient
  • CHA2DS2 VASc score
    • Congestive heart failure - 1
    • Hypertension -1
    • Age > 75 - 2
    • Diabetes Mellitus -1
    • Stroke or TIA - 2
    • Vascular disease - 1
    • Age - 65 -74
    • Sex - Female
  • Score 0 low risk, no anticoagulation or aspirin 81-324
  • Score 1, moderate risk, oral anticoagulation or Aspirin
  • Score 2 or more, oral anticoagulation

Don't

• Don't use Digoxin as a single agent for rate control.
• Don't use calcium channel blocker, beta blocker, and digoxin in atrial fibrillation patients with WPW

References

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