Atrial fibrillation resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vidit Bhargava, M.B.B.S [2]; Hilda Mahmoudi M.D., M.P.H.^[3]; Priyamvada Singh, M.D. [4]

Definitions

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

Primary AF is classified as shown below:

Definitions

▸ Paroxysmal - AF lasting < 7 days (most last < 24 hours). Usually self terminating.

▸ Persistent - AF lasting > 7 days. Usually does not terminate on its own.

▸ Permanent - AF lasting for a longer period, where in attempted cardioversion has failed or promises no improvement.

▸ Lone AF - AF in patients > 60 years, without any pre-existing cardiopulomunary diseases.

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

Shown below is an algorithm summarizing the initial approach to evaluation of AF.

		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 ❑ Pulmonary 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: Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Newly discovered AF

Paroxysmal AF

Persistent AF

❑ 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: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy Heart rate control: ❑ Control heart rate as an initial method to manage AF, and regulate ventricular output Click here for pharmacological agents and doses used to control heart rate

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 (Class of recommendation I Level of evidence A) ❑ Measure INR weekly initially, then monthly when stable (Class of recommendation I Level of evidence A) ❑ Reassess need for anticoagulation at periodic intervals (Class of recommendation IIa Level of evidence C)

Antiarrhythmic therapy: ❑ Consider antiarrhythmic therapy for maintenance of sinus rhythm Click here for recommended pharmacological agents used for maintenance of sinus rhythm

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

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

Recurrent Paroxysmal Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with recurrent paroxysmal atrial fibrillation: Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Recurrent paroxysmal AF

Minimal or no symptoms

Disabling symptoms in AF

Anticoagulation: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy Heart rate control: ❑ Control heart rate as an initial method to manage AF, and regulate ventricular output Click here for pharmacological agents and doses used to control heart rate

Anticoagulation: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy Heart rate control: ❑ Control heart rate as an initial method to manage AF, and regulate ventricular output Click here for pharmacological agents and doses used to control heart rate

❑ Long term therapy for prevention of AF not needed

Antiarrhythmic therapy: ❑ Consider antiarrhythmic therapy for maintenance of sinus rhythm Click here for recommended pharmacological agents used for maintenance of sinus rhythm

❑ Consider AF ablation if antiarrhythmic drug treatment fails

Recurrent Persistent Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with recurrent persistent atrial fibrillation: Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Recurrent persistent AF

Minimal or no symptoms

Disabling symptoms in AF

Anticoagulation: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy Heart rate control: ❑ Control heart rate as an initial method to manage AF, and regulate ventricular output Click here for pharmacological agents and doses used to control heart rate

Anticoagulation: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy Heart rate control: ❑ Control heart rate as an initial method to manage AF, and regulate ventricular output Click here for pharmacological agents and doses used to control heart rate

Antiarrhythmic therapy: ❑ Consider antiarrhythmic therapy for maintenance of sinus rhythm Click here for recommended pharmacological agents used for maintenance of sinus rhythm

❑ Perform electrical cardioversion as needed ❑ Pretreat with one of the following agents to reduce the risk of early recurrence of AF after cardioversion: ❑ Amiodarone ❑ Flecainide ❑ Ibutilide ❑ Propafenone ❑ Sotalol

❑ Continue anticoagulation therapy based on risk factor profile as above ❑ Continue antiarrhythmic therapy to maintain sinus rhythm as above

❑ Consider ablation for severely symptomatic recurrent AF after failure of ≥ 1 antiarrhythmic drug plus rate control

Permanent Atrial Fibrillation

Shown below is an algorithm depicting the pharmacological management of patients with permanent atrial fibrillation:Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of atrial fibrillation.

Permanent AF

Anticoagulation: ❑ Consider anticoagulation as needed based on the risk of stroke ❑ Click here for the risk of stroke and anticoagulation therapy Heart rate control: ❑ Control heart rate as an initial method to manage AF, and regulate ventricular output Click here for pharmacological agents and doses used to control heart rate

Antiarrhythmic Drug Therapy in Atrial Fibrillation

Shown below is an algorithm depicting the antiarrhythmic drug therapy for maintaining sinus rhythm in patients with recurrent paroxysmal or persistent atrial fibrillation: Algorithm based on the 20011 ACCF/AHA/HRS updates for the management of 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.

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

Drug & Dosage

▸ Amiodarone (100 to 400 mg) OR ▸ Disopyramide (400 to 750 mg) OR ▸ Dofetilide (500 to 1000 mcg) OR ▸ Flecainide (200 to 300 mg) OR ▸ Procainamide (1000 to 4000 mcg) OR ▸ Propafenone (450 to 900 mg) OR ▸ Quinidine (600 to 1500 mg) OR ▸ Sotalol (160 to 320 mg)

Pharmacological Cardioversion

Cardioversion upto 7 Days

Drug	Dosage
Agents with proven efficacy
▸ Dofetilide (Class of recommendation I Level of evidence A)	▸ Creatinine clearance(ml/min): > 60 - 500 mg 40 to 60 - 250 mg 20 to 40 - 125 mg < 20 - contraindicated
▸ Flecainide (Class of recommendation I Level of evidence A)	▸ Oral: 200 to 300 mg Intravenous: 1.5 to 3.0 mg/kg over 10 to 20 min
▸ Ibutilide (Class of recommendation I Level of evidence A)	▸ 1 mg over 10 min; repeat 1 mg when necessary
▸ Propafenone (Class of recommendation I Level of evidence A)	▸ Oral: 600 mg Intravenous: 1.5 to 2.0 mg/kg over 10 to 20 min
▸ Amiodarone (Class of recommendation IIa Level of evidence 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
Agents with proven efficacy
▸ Dofetilide (Class of recommendation I Level of evidence A)	▸ Creatinine clearance(ml/min): > 60 - 500 mg 40 to 60 - 250 mg 20 to 40 - 125 mg < 20 - contraindicated
▸ Ibutilide (Class of recommendation I Level of evidence A)	▸ 1 mg over 10 min; repeat 1 mg when necessary
▸ Amiodarone (Class of recommendation IIa Level of evidence 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.

Drugs which enhance the efficacy of electric 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

Shown below is a table used to categorize the risk of stroke in a patient with AF:

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

Shown below is a table illustrating anticoagulant therapy based on risk factors:

Risk Category & Recommended Therapy

▸ No risk factors - Aspirin 81-325 mg daily OR ▸ 1 Moderate risk factor - Aspirin 81-325 mg daily or Warfarin (INR 2.0 to 3.0, target 2.5) OR ▸ 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

Shown below is a table summarizing the list of recommended agents for control of heart rate and their dosage:

Drug	Loading dose	Maintenance dose
Acute Setting
Heart rate control in patients without accessory pathway
▸ Esmolol (Class of recommendation I Level of evidence C)	▸ 500 mcg/kg IV over 1 min	▸ 60 to 200 mcg/kg/min IV
▸ Propanolol (Class of recommendation I Level of evidence C)	▸ 0.15 mg/kg IV	▸ NA
▸ Metoprolol (Class of recommendation I Level of evidence C)	▸ 2.5 to 5 mg IV bolus over 2 min; up to 3 doses	▸ NA
▸ Diltiazem (Class of recommendation I Level of evidence B)	▸ 0.25 mg/kg IV over 2 min	▸ 5 to 15 mg/h IV
▸ Verapamil (Class of recommendation I Level of evidence B)	▸ 0.075 to 0.15 mg/kg IV over 2 min	▸ NA
Heart rate control in patients with accessory pathway
▸ Amiodarone (Class of recommendation IIa Level of evidence 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
▸ Amiodarone (Class of recommendation IIa Level of evidence C)	▸ 150 mg over 10 min	▸ 0.5 to 1 mg/min IV
▸ Digoxin (Class of recommendation I Level of evidence B)	▸ 0.25 mg IV each 2 h, up to 1.5 mg	▸ 0.125 to 0.375 mg daily IV or orally
Non-Acute Setting and Chronic Maintenance Therapy
Heart rate control
▸ Metoprolol (Class of recommendation I Level of evidence C)	▸ Same as maintenance dose	▸ 25 to 100 mg twice a day, orally
▸ Propanolol (Class of recommendation I Level of evidence C)	▸ Same as maintenance dose	▸ 80 to 240 mg daily in divided doses, orally
▸ Verapamil (Class of recommendation I Level of evidence B)	▸ Same as maintenance dose	▸ 120 to 360 mg daily in divided doses; slow release available, orally
▸ Diltiazem (Class of recommendation I Level of evidence 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 (Class of recommendation I Level of evidence B)	▸ 0.5 mg by mouth daily	▸ 0.125 to 0.375 mg daily, orally
▸ Amiodarone (Class of recommendation IIb Level of evidence 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

Rate control during AF:

• Begin therapy with either a beta blocker, diltiazem, or verapamil. (Class of recommendation I Level of evidence B) Use a combination of digoxin and either a beta blocker, diltiazem, or verapamil if AF not controlled by monotherapy. (Class of recommendation IIa Level of evidence B)
• Use ablation of the arterioventricular (AV) node or accessory pathway, if pharmacological therapy is insufficient. (Class of recommendation IIa Level of evidence B)
• If rate is not controlled by above measures use oral or IV amiodarone, either alone or in combination with other agents. (Class of recommendation IIb Level of evidence C)

Antithrombotic therapy:

• Dabigatran may be used as an alternative to warfarin in those wdo don't have: (Class of recommendation I Level of evidence B)

• Prosthetic heart valve
• Hemodynamically significant valve disease
• Severe renal failure (creatinine clearance <15 mL/min) or
• Advanced liver disease (impaired baseline clotting function).

• Give anticoagulants 3 weeks prior to & 4 weeks after cardioversion for patients with unknown duration of AF or AF > 48 hours. (Class of recommendation I Level of evidence B) Those requiring immediate cardioversion should be given IV heparin, followed by 4 weeks of oral anticoagulant therapy.
• If patient on anticoagulants with AF sustains stroke or systemic embolism, target INR may be raised to 3.0 - 3.5 (Class of recommendation IIb Level of evidence C) .
• Anticoagulation therapy can be interrupted for upto 1 week, if patients needs a procedure that carries a risk of bleeding (Class of recommendation IIa Level of evidence C) . For periods > 1 week unfractionated or low molecular weight heparin may be given IV (Class of recommendation IIb Level of evidence C) .

Cardioversion:

• Use a rate control agent such as beta blocker, diltiazem or verapamil before initiating antiarrhythmic medication to prevent rapid AV conduction. (Class of recommendation IIa Level of evidence C)
• Perform cardioversion immediately in AF < 48 hours without a need for anticoagulation. (Class of recommendation I Level of evidence C)
• Transesophageal echocardiography may be used to search for thrombus prior to cardioversion, if none are found patient may be treated with 4 weeks of anticoagulants after the procedure. (Class of recommendation IIa Level of evidence B) If thrombus is found, 3 weeks of anticoagulant therapy prior and 4 weeks afterwards is a must. (Class of recommendation IIa Level of evidence C)

Don't

• Do not wait to give anticoagulants in a patient with hemodynamic instability, perform cardioversion immediately. Administer IV unfractionated heparin or SC injection of a low-molecular-weight heparin.
• Don't use digoxin as a single agent for rate control in patients with paroxysmal AF. (Class of recommendation III Level of evidence B)
• Do not attempt catheter ablation unless a trial of medication to control ventricular rate has been made. (Class of recommendation III Level of evidence C)
• Do not give IV nondihydropyridine calcium channel antagonist in a patient with decompensated heart failure and AF.
• Do not use digoxin and sotalol for pharmacological cardioversion of AF. (Class of recommendation III Level of evidence A)
• Do not start quinidine, procainamide, disopyramide, and dofetilide in out of hospital setting. (Class of recommendation III Level of evidence B)
• Do not perform repeated electric cardioversion in those with short periods of normal sinus rhythm in between. (Class of recommendation III Level of evidence C)
• Do not perform electric cardioversion in those with digitalis toxicity and/or hypokalemia. (Class of recommendation III Level of evidence C)
• Don't use calcium channel blocker, beta blocker, and digoxin in atrial fibrillation patients with WPW.

References

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