Multifocal Atrial Tachycardia Flashcards
What is the characteristic ECG finding of multifocal atrial tachycardia (MAT)?
- Distinct P waves of at least three different morphologies
- Irregular R-R intervals
- An atrial rate >100/min
What is the name for the cardiac arrhythmia that has variable P wave morphology but has a normal heart rate?
This is called wandering pacemaker.
- Wandering atrial pacemaker is an irregular rhythm with 3 or more distinct P wave morphologies.
- It is a non-tachycardic version of multifocal atrial tachycardia.
How is the atrial rate in multifocal atrial tachycardia (MAT) different from wandering atrial pacemaker?
The atrial rate in MAT is >100/min, while it is <100/min in wandering atrial pacemaker.
Which patient population is most commonly affected by multifocal atrial tachycardia (MAT)?
Heart failure patients, elderly patients (>70 years), and especially those with chronic obstructive pulmonary disease (COPD) or other pulmonary disorders.
What is the most common risk factor for multifocal atrial tachycardia?
COPD.
What are the clinical findings commonly associated with multifocal atrial tachycardia (MAT)?
Rapid, irregular pulse; symptoms of the underlying illness, such as cough, wheezing, or shortness of breath.
What are the most common causes of multifocal atrial tachycardia (MAT)?
- Exacerbation of pulmonary diseases (COPD)
- Electrolyte disturbances (e.g., hypokalemia, hypomagnesemia)
- Catecholamine surge due to an underlying illness or sepsis
What is the initial treatment for multifocal atrial tachycardia (MAT)?
Management of the underlying inciting illness, such as COPD exacerbation, with bronchodilators, systemic corticosteroids, and oxygen therapy. Some patients may require forced/noninvasive oxygen therapy.
How does noninvasive ventilation help resolve multifocal atrial tachycardia (MAT)?
It alleviates respiratory distress, reduces catecholamine surge, and improves oxygenation, which helps resolve the arrhythmia.
What electrolyte levels are appropriate to mitigate MAT?
Preferably, serum potassium should be replaced to a level of 4.0 mEq/L, and serum magnesium should be maintained at (or replaced to) a level of 2.0 mEq/L. Repletion of depleted electrolytes will often lead to conversion to sinus rhythm in patients with MAT. Electrolyte disturbances (eg, hypokalemia, hypomagnesemia) are a common cause of MAT; therefore, laboratory results show another underlying disturbance that should be addressed. Correcting electrolytes may be an important step in managing a patient’s MAT. Additionally history should be collected as well to elucidate the cause of his hypokalemia (eg, diarrhea, diuretic use).
What is the role of systemic corticosteroids in treating MAT?
They reduce inflammation in the context of pulmonary exacerbation, addressing the underlying cause of MAT.
What is the treatment for patients with refractory multifocal atrial tachycardia?
Non-dihydropyridine calcium channel blockers such as diltiazam or verapamil. Intravenous nondihydropyridine calcium channel blockers (eg, verapamil, diltiazem) and beta blockers (eg, esmolol) can be used to control the rapid ventricular rate in patients with MAT. However, these medications do not address the underlying cause of MAT, and treatment of the inciting illness is the best initial management.
What is the role of non-dihydropyridine calcium channel blockers (e.g., diltiazem) in MAT management?
They can be used to control the rapid ventricular rate but do not address the underlying cause of MAT, therefore this is typically used as a second-line treatment approach used for refractory MAT.
Why is synchronized cardioversion not appropriate for managing MAT?
Synchronized cardioversion is reserved for hemodynamically unstable supraventricular tachycardias, but MAT rarely causes hemodynamic instability.
