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

No therapy needed unless severe symptoms (hypotension, heart failure, angina pectoris

Accept permanent AF

Rate control and anticoagulation as needed

Anticoagulation as needed Recommended in all cases except lone AF (I A) Reassess need for anticoagulation at periodic intervals 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)*

Anticoagulaion and rate control* as needed

Consider antiarrhythmic drug therapy

Cardioversion

Long term antiarrhythmic drug therapy unnecessary

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 and rate control as needed

Anticoagulation and rate control as needed

No drug for prevention of AF

Antiarrhythmic drug therapy*

AF ablation if ADD treatment fails

ADD indicates antiarrhythmic drugs
*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.

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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