Atrial tachycardia

Background

  • Also known as focal atrial tachycardia
  • Rate >100 bpm
  • Electrical focus that originates outside in the sinus node at a single location
    • By comparison, reentrant tachycardias (eg. AVRT, AVNRT) involve multiple foci/ larger circuits

Clinical Features

  • Palpitations
    • non-specific finding
    • associated with all tachydysrhythmias, not just AT
    • rapid fluttering/throbbing/pounding sensation in the chest or neck
  • Syncope
    • patients with AT rarely present with syncope
    • cerebral hypoperfusion is more common with a ventricular rate >200 bpm
  • Chest pain
    • can present if there is underlying cardiovascular disease
    • represents a worsening of the associated disease
  • Dyspnea
    • can present if there is underlying cardiovascular disease
    • represents a worsening of the associated disease

Differential Diagnosis

Narrow-complex tachycardia

Evaluation

Workup

Diagnosis

  • Atrial tachycardia differs from sinus tachycardia in that the impulses are generated by an ectopic focus somewhere within the atrial myocardium rather than the sinus node.
  • The atrial (P wave), is usually 100-250 /min with abnormally shaped P waves. The combination of focal atrial tachycardia with AV block is particularly common in digoxin toxicity.
  • Multifocal atrial tachycardia can be mistaken for AF, due to its irregular nature, but closer inspection of the ECG will reveal P waves with at least three different morphologies.

Management

  • Non-sustained episodes of focal tachycardia are commonly seen on ambulatory ECG monitoring and are often asymptomatic.
  • Sustained atrial tachycardia can lead to a tachycardia-induced cardiomyopathy and it is important not to misdiagnose the rhythm as sinus tachycardia in such cases.
  • Focal atrial tachycardia should be treated with urgent electrical cardioversion if the patient is unstable.
  • Stable patients may cardiovert with adenosine or with beta blockers.
  • If digoxin toxicity is the cause of the atrial tachycardia the drug should be stopped.
  • Rate control and or prophylaxis against recurrent episodes can be attained usually with beta blockers, or calcium channel blockers.

See Also

External Links

References