Atrial Flutter – Causes, Symptoms, Diagnosis, Treatment and Ongoing care

Basics

Description

Atrial flutter (A. flutter) is a cardiac arrhythmia resulting in a (usually) narrow QRS rhythm, often tachycardia with an atrial rate of 250–350 beats per minute:

  • “Saw-toothed” P-waves are classic.
  • Ventricular rate is dependent upon AV node conduction (see Pathophysiology).
  • System(s) affected: Cardiac

Epidemiology

Incidence

  • Age: 5 per 100,000 person-years in people <50 years of age. 587 per 100,000 person-years in people >80 years of age.
  • Sex: Male > Female (2.5:1)

Risk Factors

  • Heart disease (e.g., left ventricular [LV] dysfunction), LV hypertrophy, hypertension [HTN], valvular heart disease (especially rheumatic), coronary artery disease, acute myocardial infarction [MI], atrial fibrillation [A. fib], pericarditis, history of congenital heart disease, recent cardiac surgery, atrial scarring
  • Pulmonary disease (e.g., chronic obstructive pulmonary disease [COPD], pulmonary embolism, pneumonia)
  • Hyperthyroidism
  • Obesity

Genetics

Although several genes have been identified that may predispose to A. fib, there is no definite association of these genes with A. flutter.

General Prevention

Risk factor avoidance

Pathophysiology

Most commonly caused by a rapid re-entrant circuit around the tricuspid valve (specifically, the cavotricuspid isthmus):

  • AV node conduction is variable:
    • 2:1 most common (∼150 bpm); 3:1, 4:1 possible, 1:1 more rare (>∼200 bpm)
    • Variable conduction ratios can cause irregularly irregular pulse, mimicking A. fib.

Etiology

  • Most cases associated with a predisposing factor (see Risk Factors)
  • Lone A. flutter; no predisposing factor:
    • 1.7% of patients with A. flutter
  • Digitalis toxicity; rare cause

Commonly Associated Conditions

  • See Risk Factors.
  • Atrial fibrillation patients frequently go in and out of atrial flutter.

Atrial flutter, Heart failure, Wolff–Parkinson–White syndrome, Atrioventricular block, Electrocardiogram, Wolff-Parkinson-White, acute myocardial infarction, congenital heart disease, coronary artery disease, cardiac arrhythmia, chronic obstructive pulmonary disease, Diagnosis

History

  • Common:
    • Palpitations, shortness of breath, fatigue, lightheadedness
  • Less common:
    • Chest pain, near-syncope
    • Insidious onset with fatigue or worsening of a chronic cardiac/pulmonary disease
  • Rare:
    • Syncope
    • Symptoms/signs of acute embolic stroke

Physical Exam

  • Common: Often normal exam
    • Tachycardia: May be regular or irregularly irregular
    • Mild dyspnea
    • Evidence of a predisposing factor
  • Less common:
    • Moderate dyspnea
    • CHF: More common in elderly or with prior history
  • Rarely, hemodynamic compromise occurs:
    • Hypotension
    • Severe dyspnea or respiratory failure
    • Hypoxia with cyanosis or pallor
    • Decreased level of consciousness

Diagnostic Tests & Interpretation

Lab

Initial lab tests

Complete blood count (CBC), BMP, cardiac enzymes, thyroid-stimulating hormone (TSH), digoxin level (as indicated), prothrombin time (PT)/international normalized ratio (INR) (if anticoagulated or anticoagulation being considered)

Imaging

Initial approach

  • Chest x-ray to evaluate for acute cardiopulmonary disease
  • Electrocardiogram (ECG) to evaluate for signs of ischemia, heart blocks, intervals, and for diagnosis of atrial flutter

Follow-Up & Special Considerations

  • For new-onset atrial flutter, transthoracic echocardiogram is helpful in assessing atrial size, ejection fraction, valvular function, and evaluating right-sided pressures (acute pulmonary embolism).
  • Transesophageal echocardiogram may be necessary if thrombus suspected before cardioversion.

Diagnostic Procedures/Surgery

When clinically indicated:

  • Holter monitor: If symptoms are concerning but rhythm not present at time of evaluation
  • Electrophysiologic studies should be considered in patients with recurrent A. flutter to map the source of the arrhythmia for possible ablation.

Differential Diagnosis

  • Paroxysmal supraventricular tachycardia
  • Sinus tachycardia
  • Junctional tachycardia
  • Multifocal atrial tachycardia (MAT)
  • Wolff-Parkinson-White syndrome

Treatment

Medication

First Line

  • Rate-control agents useful in the initial management, but generally not efficacious in controlling chronic or recurrent arrhythmia (1)[C]
  • Nondihydropyridine calcium channel blockers:
    • Diltiazem (Cardizem):
      • Initial dose: 0.25 mg/kg IV × 1, may give 0.35 mg/kg IV × 1 after 15 min if needed
      • Maintenance: 5–15 mg/h IV up to 24 hours
    • Verapamil (Isoptin, Calan, Verelan):
      • As efficacious as diltiazem; increased hypotension (1)
    • Class contraindications: Hypotension, documented sensitivity, 2nd- or 3rd-degree AV block, severe CHF, sick sinus syndrome
    • Precautions: Use caution with CHF, left ventricular (LV) dysfunction, liver or kidney disease
    • Interactions: May increase digoxin levels; with amiodarone or beta-blockers, may severely decrease cardiac output, trigger complete heart block
    • Adverse reactions: Hypotension, CHF, peripheral edema, AV block
  • Beta-blockers:
    • Metoprolol (Lopressor):
      • Initial: 5 mg IV, repeat q5min; max, 15 mg
      • Maintenance: 5–15 mg IV q3–6h
    • Esmolol (Brevibloc):
      • Initial dose: 500 mcg/kg IV over 1 minute, repeat q4min to total of 3 doses if needed
      • Maintenance: 50 mcg/kg/min, increased by 50 mcg/kg/min q4min p.r.n.; max of 200 mcg/kg/min
      • Half-life ∼8 min; good choice for patients at risk for complications
    • Contraindications: Hypotension, documented sensitivity, 2nd- or 3rd-degree AV block, severe CHF, sick sinus syndrome
    • Precautions: Use caution with CHF, LV dysfunction, kidney disease, or asthma.
    • Interactions: Bradycardia with digoxin; with amiodarone or calcium channel blockers may severely decrease cardiac output or trigger complete heart block
    • Adverse reactions: Hypotension, CHF, peripheral edema, AV block
  • Digoxin (Lanoxin):
    • Indicated for CHF, hypotension
    • Initial dose: 0.75–1.25 mg p.o. or 0.5–1 mg IV divided 50% initially, then 25% × 2 q6–12h
    • Maintenance: 0.125–0.5 mg/d p.o. or 0.1–0.4 mg/d IV
    • Therapeutic level: 0.8–2 ng/mL
    • Contraindications: Documented sensitivity, sick sinus syndrome, hypertrophic cardiomyopathy
    • Precautions: Use caution with electrolyte abnormalities (especially hypokalemia, hypercalcemia), impaired renal function, thyroid disease, acute myocardial infarction (MI), and AV block.
  • Interactions: Unpredictable effects with many antiarrhythmics; additive bradycardia with calcium channel blockers, beta-blockers
  • Adverse reactions: AV block, bradycardia, mental disturbances, nausea
  • Rate control usually achieved in 4 hours (1).

Second Line

  • Pharmacologic cardioversion is 2nd-line to electrical cardioversion in restoring sinus rhythm.
  • Pure class III antiarrhythmics:
    • Ibutilide (Corvert) IV:
      • Initial dose: <60 kg, 0.01 mg/kg over 10 minutes; 60 kg, 1 mg over 10 minutes; may repeat in 10 minutes p.r.n.
    • Dofetilide (Tikosyn) Oral:
      • Dosing: Dependent on QTc interval and creatinine clearance; see package insert
    • Contraindications: Documented sensitivity, QTc >440 ms, use of a class I or III antiarrhythmic within 4 hours, structural heart disease, sinus node disease
    • Precautions: Correct hypokalemia and hypomagnesium prior to use; use caution in AV block, CHF, QT prolongation, renal/hepatic disease, and elderly patients.
    • Interactions: Many antiarrhythmics have unpredictable effects with digoxin; additive bradycardia with calcium channel blockers and beta-blockers.
    • Adverse reactions: Polymorphic VT/torsades de pointes (1.5–3%), AV block, QT prolongation, CHF, renal failure, allergy, hypotension, HTN, headache (4%)
    • Efficacy = 60–70% (1)

Additional Treatment

General Measures

  • Identify and treat underlying causes first.
  • A. flutter often self-resolves within days:
    • Watchful waiting may be appropriate in hemodynamically stable patients, particularly with a reversible predisposing cause and normal left atrial size.
  • Restoration of normal sinus rhythm is generally the goal of therapy (1)[C]:
    • Self-limited A. flutter related to an underlying cause rarely requires chronic therapy (1)[C].
    • >50% of patients with chronic or recurrent A. flutter experience recurrence within 1 year of successful cardioversion (2).

Issues for Referral

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Cardiology referral recommended for refractory cases and for ablation.

Additional Therapies

  • Anticoagulation for cardioversion: If >48 hrs duration, recommend warfarin anticoagulation (INR 2–3) 3 weeks before and 4 weeks after cardioversion (3)[B].
  • If immediate cardioversion needed for hemodynamic instability in A. flutter >48 hrs or unknown, bridge with heparin (regular or LMWH) until warfarin therapeutic. Treat for 4 weeks. None needed for <48 hrs (3)[C].
  • If TEE (-) for thrombus, no prior anticoagulation needed, but heparin bridge to 3–4 weeks of warfarin therapy (2)[B]. If (+) then treat as if >48 hrs. Longer post-cardioversion AC (3)[C].

Surgery/Other Procedures

Catheter ablation is the treatment of choice for patients with recurrent or chronic A. flutter (1)[A]. 80% remain in sinus rhythm at 21 months compared to 36% with antiarrhythmics (1). To prevent rehospitalization with ablation compared to antiarrhythmics, NNT is 2.2 (1). Catheter ablation results in improved symptoms and improved quality of life (1).

In-Patient Considerations

Initial Stabilization

1st priority is to determine stability of patient:

  • Hemodynamically stable:
    • Consider calcium channel blocker or beta-blocker for rate control (1)[C].
  • Hemodynamically unstable (see Physical Exam: Hemodynamic compromise):
    • DC cardioversion is best treatment (1)[C].
    • Begin with dose of 50 J (with biphasic defibrillator) or 200 J (with monophasic defibrillator) and increase as needed (1)[C].
    • Atrial overdrive pacing also effective (1)[C]

Admission Criteria

  • Most patients with 1st diagnosis of persistent A. flutter require admission for cardiac monitoring.
  • All patients who cannot be rate-controlled in the outpatient setting should be admitted.
  • Patients with hemodynamic compromise may require intensive care unit (ICU) admission.

IV Fluids

  • If hemodynamic unstable, use fluid boluses to maintain blood pressure (BP).
  • Caution in LV dysfunction: Avoid CHF.
  • If n.p.o., use appropriate maintenance fluid.

Nursing

Strict I/O

Discharge Criteria

Patients can be discharged if rate-controlled, but typically they are when back in NSR.

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

Telemetry

Diet

n.p.o. until rate controlled

Complications

  • Incidence of embolization with A. flutter is similar to that of A. fib: 1.7–7% (1).
  • Hemodynamic instability, CHF

References

1. Blomström-Lundqvist C, Scheinman MM, Aliot EM et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias–executive summary. a report of the American college of cardiology/American heart association task force on practice guidelines and the European society of cardiology committee for practice guidelines (writing committee to develop guidelines for the management of patients with supraventricular arrhythmias) developed in collaboration with NASPE-Heart Rhythm Society. J Am Coll Cardiol. 2003;42:1493–531.

2. Crijns HJ, Van Gelder IC, Tieleman RG et al. Long-term outcome of electrical cardioversion in patients with chronic atrial flutter. Heart. 1997;77:56–61.

3. Fuster V, Ryden L, et al. ACC/AHA/ESC Guidelines for the management of Patients with Atrial Fibrillation. Circulation. 2006;114:257–354.

Additional Reading

Scholten MF, Thornton AS, Mekel JM et al. Anticoagulation in atrial fibrillation and flutter. Europace. 2005;7:492–9.

See Also (Topic, Algorithm, Electronic Media Element)

Atrial Fibrillation

Codes

ICD9

427.32 Atrial flutter

Snomed

5370000 Atrial flutter (disorder)

Clinical Pearls

  • Atrial flutter is an unstable rhythm and will sometimes spontaneously resolve.
  • Goals of care should be stabilization and rate control.
  • Catheter ablation is the treatment of choice for recurrent or chronic atrial flutter.

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