Atrial flutter

Background

• Supraventricular Tachycardia
  • Atrial re-entry circuit
• Defined by atrial rate of 250-350, classically 300

Clinical Presentation

• Asymptomatic
• Palpitations
• Fatigue
• Dyspnea
• Pre-syncope/syncope

Differential Diagnosis

• Can be difficult to distinguish from atrial fibrillation

Palpitations

• Arrhythmias:
  • Narrow-complex tachycardias
  • Wide-complex tachycardias
  • AV blocks
    • Second Degree AV Block Type I (Wenckeback)
    • Second Degree AV Block Type II
    • Third Degree AV Block
  • Premature atrial contraction
  • Premature junctional contraction
  • Premature ventricular contraction
  • Sick sinus syndrome
  • Wandering atrial pacemaker
• Non-arrhythmic cardiac causes:
  • Acute coronary syndrome
  • Cardiomyopathy
  • Congenital heart disease
  • Congestive heart failure (CHF)
  • Mitral valve prolapse
  • Pacemaker complication
  • Pericarditis
  • Myocarditis
  • Valvular disease
• Psychiatric causes:
  • Panic attack
  • Anxiety
  • Somatic Symptom Disorder
• Drugs and Medications:
  • Alcohol
  • Caffeine
  • Drugs of abuse (e.g. cocaine)
  • Medications (e.g. digoxin, theophylline)
  • Tobacco
• Misc
  • Anemia
  • Hyperthyroidism
    • Thyroid storm
  • Pulmonary embolism
  • Dehydration
  • Sepsis
  • Pheochromocytoma

Diagnosis

Atrial flutter with variable block

ECG

• Narrow complex tachycardia
• Atrial rate near 300
• Flutter waves (sawtooth pattern) in inferior leads
• AV nodal conduction
  • 1:1 conduction can be unstable
    • Suggests pre-excitation, sympathetic excess, parasympathetic withdrawal, Class 1C anti-arrhythmic use
  • 2:1 conduction is most common
    • Suspect atrial flutter whenever ventricular rate is 150
  • conduction >2:1
    • More commonly even ratio
    • Suggests AV nodal blocking agents or AV node disease
  • Variable block
    • Difficult to distinguish from atrial fibrillation
    • Look for: R-R interval that is multiple of P-P interval and mathematical relationship between R-R intervals
    • A-fib is completely irregular with no relationship between intervals

Types

• Type 1 (Typical Atrial Flutter)
  • Re-entry circuit of right atrium (IVC and tricuspid valve)
    • Anticlockwise circuit- 90% of cases
      • Inverted flutter waves in inferior leads
      • Positive flutter waves in V1
    • Clockwise circuit
      • Positive flutter waves in inferior leads
      • Inverted flutter waves in V1
• Type 2 (Atypical Atrial Flutter)
  • Does not meet criteria for typical atrial flutter
  • Less amenable to treatment

See Also

Atrial fibrillation

References

• Rosen's