Atrial flutter resident survival guide

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]

Atrial fibrillation resident survival guide Microchapters
Overview
Causes
Diagnosis
Treatment
Heart Rate Control
Pharmacological Cardioverion
Antiarrhythmic Therapy
Anticoagulation Therapy
Do's
Dont's

Overview

Atrial flutter is a reenterant arrhythmia, with atrial rates between 240 and 340/min, with a regular ventricular response and a saw tooth pattern on EKG. While it occurs mostly in patients with structural heart disease, it may also occur in patients with normal heart. It presents with palpitations, dyspnea, fatigue, lightheadedness etc. A typical flutter rhythm on EKG consists of absent P waves, saw tooth pattern in leads II, III and aVF, an atrial rate of 240-340 beats/min and an atrial rate:ventricular rate ratio 2:1 (most commonly). The treatment consists of rate control, anticoagulation therapy and cardioversion if the flutter is well tolerated. In those with poorly tolerated flutter or hemodynamic instability direct DC cardioversion is attempted, followed by rate control therapy.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Atrial flutter can be a life-threatening condition and must be treated as such irrespective of the causes.

Common Causes

• Acute coronary syndromes
• Cardiomyopathy
• Carbon monoxide poisoning
• Congenital heart disease
• Hypertensive heart disease
• Hyperthyroidism
• Mitral valve disease
• Pulmonary embolism
• Myocardial infarction

Management

Diagnostic Approach

Shown below is an algorithm summarizing the initial approach to atrial flutter.

		Characterize the symptoms: ❑ Asymptomatic ❑ Palpitations ❑ Dyspnea ❑ Fatigue ❑ Chest discomfort ❑ Lightheadedness ❑ Syncope/Presyncope ❑ Tachycardia ❑ Weakness Characterize the timing of the symptoms: ❑ Onset ❑ First episode ❑ Recurrent ❑ Duration ❑ Frequency ❑ Termination of the episode ❑ Spontaneous ❑ Medication use ❑ Not terminated
		Identify possible triggers: ❑ Infection ❑ Caffeine ❑ Alcohol ❑ Nicotine ❑ Recreational drugs ❑ Hypovolemia ❑ Hyperthyroidism ❑ Hypoxia ❑ Acidosis ❑ Hypokalemia ❑ Hyperkalemia ❑ Hypoglycemia ❑ Treatment of Atrial fibrillation ❑ Acute myocardial infarction ❑ Digitalis toxicity ❑ Hypothermia ❑ Toxins ❑ Cardiac tamponade ❑ Post cardiac surgery ❑ Coronary thrombosis ❑ Trauma ❑ Pulmonary embolism
		Examine the patient: ❑ Tachycardia ❑ Hypotension - suggestive of ventricular dysfunction ❑ Diaphoresis ❑ Evidence of congestive heart failure ❑ Flutter waves in jugular vein ❑ Signs of embolization Pulmonary: ❑ Dyspnea ❑ Tachypnea ❑ Chest pain ❑ Hemoptysis Arterial: ❑ Cold extremities ❑ Loss of distal pulsations ❑ Pallor of the extremity ❑ Muscle pain/spasm in concerned area ❑ Weakness/lack of movement ❑ Tingling and numbness ❑ Order an ECG ♦ Atrial flutter rhythm ❑ Absent P waves ❑ Atrial rate 240-340 beats/minute ❑ Atrial rate:ventricular rate ratio 2:1 (most commonly) ❑ Saw tooth pattern in leads II, III, and aVF ♦ Other signs on ECG ❑ Left ventricular hypertrophy ❑ Preexcitation ❑ Bundle branch block ❑ Previous myocardial infarction ❑ Other types of arrhythmias
		Order labs: ❑ Order a transthoracic echocardiogram ❑ Holter monitoring ❑ Exercise testing ❑ Order blood tests (if Atrial flutter has not been investigated before) ❑ Thyroid function ❑ Renal function ❑ Hepatic function

Therapeutic Approach

Shown below is an algorithm summarizing the therapeutic approach to atrial flutter.

Atrial flutter

Unstable

Stable

❑ Look for the presence of any of these: ❑ Chronic heart failure ❑ Hypotension ❑ Acute myocardial infarction ❑ If present, attempt direct DC cardioversion and then rate control measures as shown in the table below: ▸ Conversion ▸ DC cardioversion < 50 J energy with monophasic shocks (class I, level of evidence C) ▸ Rate control ▸ Beta blockers (class IIa, level of evidence C) or ▸ Verapamil or diltiazem (class IIa, level of evidence C) or ▸ Digitalis (class IIb, level of evidence C) or ▸ Amiodarone (class IIb, level of evidence C)

❑ Administer anticoagulation therapy based on the risk of stroke, if total duration of flutter > 48 hours ❑ Administer rate control therapy as shown in table below: ▸ Rate control ▸ Beta blockers (class IIa, level of evidence C) or ▸ Verapamil or diltiazem (class IIa, level of evidence C) or ▸ Digitalis (class IIb, level of evidence C) or ▸ Amiodarone (class IIb, level of evidence C)

❑ Attempt Conversion as shown in table below: ▸ Conversion ▸ Atrial or transesophageal pacing (class I, level of evidence A) or ▸ DC cardioversion (class I, level of evidence C) or ▸ Ibutilide (class IIa, level of evidence A) or Flecainide (class IIb, level of evidence A) or Propafenone (class IIb, level of evidence A) or Sotalol (class IIb, level of evidence C) or Procainamide (class IIb, level of evidence A) or Amiodarone (class IIb, level of evidence C)

❑ Assess need for therapy to prevent recurrence

❑ Administer antiarrhythmic therapy to prevent recurrences as shown below: ▸ First episode and well-tolerated atrial flutter ▸ Cardioversion alone (class I, level of evidence B) or ▸ Catheter ablation (class IIa, level of evidence B) ▸ Recurrent and well-tolerated atrial flutter ▸ Catheter ablation(class I, level of evidence B) or ▸ Dofetilide (class IIa, level of evidence C) or ▸ Amiodarone (class IIb, level of evidence C) or Sotalol or Flecainide or Quinidine or Propafenone or Procainamide or Disopyramide ▸ Poorly tolerated atrial flutter ▸ Catheter ablation (class I, level of evidence B) ▸ Atrial flutter appearing after use of class Ic agents or amiodarone for treatment of AF ▸ Catheter ablation (class I, level of evidence B) or ▸ Stop current drug and use another (class IIa, level of evidence C) ▸ Symptomatic non–cavotricuspid isthmus-dependent flutter after failed antiarrhythmic therapy Catheter ablation (class IIa, level of evidence B) ❑ Consider Catheter ablation if antiarrhythmic therapy fails

Heart Rate Control

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

Heart Rate Control in Acute Setting Drug Loading dose Maintenance dose Heart rate control in patients without accessory pathway ▸ Esmolol (class I, level of evidence C) ▸ 500 mcg/kg IV over 1 min ▸ 60 to 200 mcg/kg/min IV ▸ Propanolol (class I, level of evidence C) ▸ 0.15 mg/kg IV ▸ NA ▸ Metoprolol (class I, level of evidence C) ▸ 2.5 to 5 mg IV bolus over 2 min; up to 3 doses ▸ NA ▸ Diltiazem (class I, level of evidence B) ▸ 0.25 mg/kg IV over 2 min ▸ 5 to 15 mg/h IV ▸ Verapamil (class 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 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 ▸ Digoxin (class 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 ▸ Amiodarone (class IIa, level of evidence C) ▸ 150 mg over 10 min ▸ 0.5 to 1 mg/min IV Heart Rate Control in Non Acute Setting and Long Term Maintenance Heart rate control ▸ Metoprolol (class I, level of evidence C) ▸ 25 to 100 mg twice a day, orally ▸ 25 to 100 mg twice a day, orally ▸ Propanolol (class I, level of evidence C) ▸ 80 to 240 mg daily in divided doses, orally ▸ 80 to 240 mg daily in divided doses, orally ▸ Verapamil (class I, level of evidence B) ▸ 120 to 360 mg daily in divided doses, orally ▸ 120 to 360 mg daily in divided doses, orally ▸ Diltiazem (class I, level of evidence B) ▸ 120 to 360 mg daily in divided doses, orally ▸ 120 to 360 mg daily in divided doses, orally Heart Rate Control in patients with heart failure and without accessory pathway ▸ Digoxin (class I, level of evidence B) ▸ 0.5 mg by mouth daily ▸ 0.125 to 0.375 mg daily, orally ▸ Amiodarone (class IIb, level of evidence C) ▸ 800 mg daily for 1 week, orally 600 mg daily for 1 week, orally 400 mg daily for 4 to 6 week, orally ▸ 200 mg daily, orally

Pharmacological cardioversion

Pharmacological Cardioversion for Atrial Flutter Drug Dosage ▸ Flecainide (class 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 I, level of evidence A) ▸ Intravenous: 1 mg over 10 min, repeat 1 mg if necessary ▸ Propafenone (class I, level of evidence A) ▸ Oral: 600 mg ▸ Intravenous: 1.5 to 2.0 mg/kg, over 10 to 20 min ▸ Amiodarone (class IIa, level of evidence A) ▸ Oral: Inpatient ▸ 1.2 to 1.8 g per day in divided dose until a maximum of 10 g ▸ Followed by a maintenance dose of 200 to 400 mg per day or 30 mg/kg Outpatient ▸ 600 to 800 mg per day divided dose until a maximum of 10 g ▸ Followed by a maintenance dose of 200 to 400 mg per day ▸ Intravenous: 5 to 7 mg/kg, over 30 to 60 min Followed by 1.2 to 1.8 g per day continuous IV OR 5 to 7 mg/kg, in divided oral doses until a maximum of 10 g Followe by a maintenance dose of 200 to 400 mg per day

Antiarrhythmic Therapy

Maintenance of Sinus Rhythm ▸ 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)

Anticoagulation Therapy

Shown below are tables depicting the assessment of risk of stroke and the appropriate anticoagulation therapy among patients with Atrial flutter.

Anticoagulation 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)

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

Do's

• Class Ic drugs can enhance AV conduction by slowing the atrial rate, so combine them with AV nodal blocking agents such as beta blockers or calcium channel blockers.
• Prefer dofetilide or ibutilide over sotalol or class I agents, though the former have a slightly higher rate of torsades de pointes.
• Prefer direct current DC cardioversion when rapid termination of flutter is needed.
• Prefer overdrive pacing in patients with flutter after cardiac surgery, it also facilitates conversion by drugs.

Don'ts

• Do not use IV ibutilide in patients with structural cardiac diseases or prolonged QT interval or in those with sinus node disease.

References

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