atrial tachycardia

Introduction

Atrial tachycardia generally occurs secondary to increased automaticity & less frequently to re-entry. Atrial tachycardia with AV block may also occur, generally 2:1 block but may be as much as 4:1 block.

Etiology

• coronary artery disease
• chronic lung disease especially with AV block
• acute alcohol ingestion
• digitalis toxicity especially with AV block
• increased automaticity
• re-entry
• electrolyte abnormalities
  • hypokalemia especially with AV block

Clinical manifestations

• may be difficult to distinguish from atrial flutter
• may be asymptomatic
• palpitations
• dizziness
• dyspnea

Diagnostic procedures

• electrocardiogram:
  • atrial rate of 130-200/min
  • p-waves have abnormal configuration & axis
  • isoelectric interval between p-waves
  • PR interval depends upon the atrial rate
  • QRS complex
    • may be normal
    • may show bundle branch block secondary to increased rate
  • 2nd degree AV block associated with digitalis toxicity

Management

• correct underlying precipitating factors
• digitalis toxicity (PAT)
  • discontinue digitalis
  • normalize serum potassium levels
  • symptomatic refractory PAT
    • lidocaine
    • propranolol
    • phenytoin
• conditions not associated with digitalis
  • Ca+2-channel blockers
  • beta-adrenergic receptor antagonists
  • digitalis
• cardioversion
  • indication: persistent atrial tachycardia
  • chemical cardioversion with class Ia, Ic or III anti- arrhythmic agents
  • synchronized DC cardioversion (50 joules)
• radio frequency catheter ablation
  • highly successful
  • condition may recur
• surgical ablation
• no benefit for stroke prevention, excess major bleeding with anticoagulation

More general terms

• supraventricular tachycardia (SVT)

More specific terms

• multifocal (chaotic) atrial tachycardia (MAT)
• paroxysmal atrial tachycardia (PAT)

Additional terms

• atrial fibrillation (AF)
• atrial flutter
• cardiac conduction re-entry