Multifocal atrial tachycardia

Background

• 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
• Electrolyte abnormalities
• Other associations
  • Valvular heart disease
  • DM
  • Acute renal failure
  • Postoperative state
  • Pulmonary embolism
  • Pneumonia
  • Anemia

Clinical Features

• Palpitations
• Dyspnea
• Chest pain
• Presyncope/syncope

Multifocal atrial tachycardia

Differential Diagnosis

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

• ECG
  • Irregular tachycardia (>100 bpm)
  • At least 3 distinct p wave morphologies
  • No dominant pacemaker site
• BMP
• Magnesium level
• Hb/Hct
• Consider infectious disease w/u
• Consider ABG/VBG

Management

• Treat the 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 BB/CCB in hemodynamically stable patient (caution with pulmonary disease)
• Cardioversion not definitive, likely recurrence if underlying illness not addressed

Disposition

• Disposition depends on the underlying illness, but often requires admission due to illness severity/age
• Poor prognostic sign when developed during hospitalization/illness
  • 60% in hospital mortality
  • mean survival around 1 year
  • Due to illness not arrhythmia

Sources

• Rosen's
• Burns, E. Multifocal Atrial Tachycardia [Web log post]. Retrieved April, 29, 2015, from http://lifeinthefastlane.com
• Tandon N et al. Multifocal Atrial Tachycardia Overview of Multifocal Atrial Tachycardia. eMedicine. Dec 3, 2015. http://emedicine.medscape.com/article/155825-overview#showall