Multifocal atrial tachycardia

Background

Rhythm strip of multifocal atrial tachycardia.

• Multiple (3 or more) ectopic foci in the atria causing an irregular atrial tachycardia
• Increased automaticity due to causes listed below

Causes

• COPD
• CHF
• Sepsis
• Methylxanthine toxicity / Theophylline toxicity
• Electrolyte abnormalities
• Other associations
  • Valvular heart disease
  • DM
  • Acute renal failure
  • Postoperative state
  • Pulmonary embolism
  • Pneumonia
  • Anemia
  • Digoxin toxicity

Clinical Features

• Palpitations
• Dyspnea
• Chest pain
• Presyncope/syncope

Differential Diagnosis

Narrow-complex tachycardia

• Regular
  • AV Node Independent
    • Sinus tachycardia
    • Atrial tachycardia (uni-focal or multi-focal)
    • Atrial fibrillation
    • Atrial flutter
    • Idiopathic fascicular left ventricular tachycardia
  • AV Node Dependent
    • Paroxysmal supraventricular tachycardia (PSVT)
      • AV node re-entry tachycardia (AVNRT)
      • AV re-entry tachycardia (AVRT)
        • Lown-Ganong-Levine syndrome
        • Wolff–Parkinson–White syndrome
    • Junctional tachycardia
• Irregular
  • Multifocal atrial tachycardia (MAT)
  • Sinus tachycardia with frequent PACs, PJCs, PVCs
  • Atrial fibrillation
    • Atrial fibrillation with RVR
  • Atrial flutter with variable conduction
  • Digoxin Toxicity

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

Evaluation

Multifocal atrial tachycardia

• ECG
  • Irregular tachycardia (>100 bpm)
  • At least 3 distinct p wave morphologies with different P-R intervals
  • No dominant pacemaker site
• BMP, Magnesium
• Hemoglobin/hematocrit
• Consider infectious disease work up
• Consider ABG/VBG

Management

• Treat underlying cause
• Replace magnesium
• Replace potassium
• Increased AV nodal activity is unlikely to be effective
  • Vagal maneuvers and adenosine may help reveal underlying rhythm/p-waves
  • Can consider beta-blocker or calcium channel blocker in hemodynamically stable patient
    • Use beta-blockers cautiously in patients with pulmonary disease
• Cardioversion not definitive
  • MAT likely to recur if underlying etiology not addressed

Disposition

• Disposition depends on underlying illness, but often requires admission due to illness severity
• Poor prognostic sign when MAT develops during hospitalization or acute illness
  • 60% in-hospital mortality
    • Due to illness, not arrhythmia
  • Mean survival around 1 year

See Also

• Dysrhythmias