II. Pathophysiology

  1. Right atrial reentry circuit around the tricuspid ring
  2. Macro-reentry Tachycardia
    1. Reentry around the entire atrium
    2. Contrast with micro reentry circuits around smaller regions (e.g. AV Node)

III. Types

  1. Type I Atrial Flutter (typical)
    1. Constant atrial rate of 240 to 350 beats per minute
    2. Ventricular rate will usually be at least a 2:1 block (AV Node prevents rates above 180)
    3. Natural rate is altered by age, atrial dilation and Antiarrhythmics (esp Type Ia or Type Ic)
  2. Type II
    1. Constant atrial rate at 340 to 440 beats per minute (Faster Atrial Flutter rate than with Type I)
    2. Differs from Type I in reentry accessory path

IV. Signs

  1. Constant atrial rate
    1. Atrial to ventricular rates may range from 1:1 to 4:1
    2. Atrial to ventricular rate 2 to 1 (most common)
      1. Atrial rate of 240 to 350 beats per minute
      2. Ventricular rate 140-150 beats per minute

V. Diagnostics: EKG

  1. Constant atrial rate
    1. Atrial rate: 300 per minute (typical)
    2. Atrial to ventricular rate
      1. Ratio 1:1 - 300 bpm (Rare, but potentially lethal)
      2. Ratio 2:1 - 150 bpm (most common)
      3. Ratio 4:1 - 75 bpm
  2. Saw tooth Flutter Waves (F Wave)
    1. Flutter Waves are best seen in the inferior leads
    2. May be difficult to visualize at a 2:1 AV Block (rate 140-150) due to overlapping QRS Complex with Flutter Wave
    3. Increase EKG "paper speed" to 50 mm/sec (rapid) to spread out complexes (P Waves may be seen)
  3. Images
    1. cvEKGAtrialFlutter4to1SawTooth.jpg

VI. Management

  1. See Atrial Fibrillation Management
  2. Highly responsive to Synchronized Cardioversion at low energy levels
    1. Dr. Amal Mattu (paraphrased): "you could rub your shoes on the carpet to shock Atrial Flutter back to sinus"

VII. References

  1. Berberian (2023) Crit Dec Emerg Med 37(3): 14-5

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