DESCRIPTION 
- Multifocal atrial tachycardia (MAT) is characterized by a rate >100 bpm and the following:
- Discrete P waves of varying morphology from at least three different foci
- Irregular variation in PP, PR, and RR intervals reflecting absence of dominant pacemaker
- Isoelectric baseline between P waves
- Synonym(s): Chaotic atrial rhythm; Chaotic atrial tachycardia
EPIDEMIOLOGY
- May occur at any age, but usually in older individuals
- Rarely seen in children and then occurs in the absence of structural heart disease and is usually self-limited (months)
- Although MAT occurs primarily in patients with lung disease in ICUs, it can occur in critically ill patients in any setting.
Prevalence
Prevalence depends on level of sickness of population and location where assessment is performed.
RISK FACTORS
- Chronic lung disease
- Recent surgery
- Diabetes
ETIOLOGY
MAT usually occurs during critical illness, especially in the setting of chronic lung disease. 
-Agonists and methylxanthine derivatives (theophylline) may be contributory.
COMMONLY ASSOCIATED CONDITIONS
See above regarding Etiology.
Outline
Signs and symptoms:
- None
- Palpitations
- Dyspnea
- Hypotension
DIAGNOSTIC TESTS & INTERPRETATION
- EKG is the only diagnostic test.
- Discrete P waves of varying morphology from at least three different foci
- Atrial rate >100 bpm
- Isoelectric baseline between P waves
- Irregular variation in PP, PR, and RR intervals reflecting absence of dominant pacemaker
DIFFERENTIAL DIAGNOSIS
- Wandering atrial pacemaker (multiple P-wave morphologies, but average atrial rate <100 bpm; common in elderly patients who are otherwise well)
- Multiple premature atrial contractions (can identify dominant, eg, sinus, P waves)
- Atrial fibrillation (no clear P waves)
- Atrial tachycardia (regular with only one morphology P wave)
Outline
- Verapamil usual drug of choice
- Amiodarone reported to be useful in children with MAT in need of therapy
- Precautions:
- Use of -blockers is controversial, and they may be difficult if not impossible to use in patients with serious lung disease.
- Digoxin is not helpful.
- Classic antiarrhythmics are not useful (procainamide, quinidine).
- Alternative drugs:
First Line
Electrical cardioversion is NOT helpful.
ADDITIONAL TREATMENT
General Measures
- Optimize pulmonary and general care.
- Reverse causes of illness and debility.
- Avoid theophylline.
IN-PATIENT CONSIDERATIONS
Admission Criteria
Usually arrhythmia is 1st recognized in inpatients. Discharge is determined by resolution of other medical problems.
Outline
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
- MAT is usually an acute problem and does not require long-term monitoring following hospital release.
- During the acute phase, be vigilant for hypotension, hypoxia, and excessive myocardial demand.
- Caregivers should maintain nutrition, especially in ICUs.
PROGNOSIS
Depends on underlying disease
Outline
CODES
ICD9
427.89 Other, specified cardiac dysrhythmias
SNOMED
49982000 multifocal atrial tachycardia (disorder)