Atrial Flutter

Atrial flutter is a supraventricular tachyarrhythmia that is usually caused by a macroreentrant rhythm within the atria.

• Incidence: 88 per 100,000 person-years (increases with age)

• Sex: ♂ > ♀ (incidence in men is 2.5 times greater than in women)

• Similar to atrial fibrillation (see “Etiology” section above)

• May additionally result from the treatment of Afib

• Type I (common; typical or isthmus-dependent flutter): caused by a counterclockwise (more common) or clockwise (less common) macroreentrant activation of cardiac muscle fibers in the right atrium that travels along the tricuspid annulus and passes through the cavotricuspid isthmus

• Type II (rare; atypical atrial flutter): various reentrant rhythms that do not involve the cavotricuspid isthmus, are not well-defined, and/or occur in the left atrium

• Most patients are asymptomatic.

• Less commonly: symptoms of arrhythmias, such as palpitations, dizziness, syncope, fatigue, and or dyspnea

• Tachycardia with a regular pulse

• Symptoms of the underlying disease (e.g., murmurs of mitral stenosis) may be present.

• Similar to atrial fibrillation except for ECG findings (see “Diagnosis of atrial fibrillation”)

• Characteristic ECG findings

  • Rate: typically 75–150/minute (depending on conduction) [56]

  • Atrial rate ≥ ventricular rate

  • Regular, narrow QRS complexes

  • The rhythm may be:

    • Regularly irregular if atrial flutter occurs with a variable AV block occurring in a fixed pattern (2:1 or 4:1)

    • Irregularly irregular with a variable block occurring in a nonfixed pattern

  • Sawtooth appearance of P waves: identical flutter waves (F waves) that occur in sequence at a rate of ∼ 300/minute

• Same as Afib (see “Treatment of atrial fibrillation” for further details)

• Rate control: more difficult to achieve in atrial flutter than in Afib [19]

• Rhythm control

  • Better results and lower recurrence compared to Afib [5][56]

  • Catheter ablation may be the most effective rhythm control strategy.

• The same parameters for anticoagulation in Afib are recommended

• Frequently degenerates into atrial fibrillation

• 1:1 conduction leading to life-threatening ventricular tachycardia