Management of Multifocal Atrial Tachycardia

Initial Management

The European Society of Cardiology recommends correcting precipitating factors as the first step in managing multifocal atrial tachycardia, with a Class I recommendation for optimizing treatment of COPD exacerbation with bronchodilators, corticosteroids, and oxygen therapy to correct hypoxemia 1, 2
The American Heart Association suggests correcting hypoxemia and acidosis immediately, which is a Class I recommendation for patients with acute pulmonary illness 1, 2
Discontinuing or reducing theophylline is recommended if the patient is receiving it, as this commonly precipitates MAT, according to the European Heart Journal 1, 2
Avoiding or minimizing β-adrenergic agonists is recommended when possible, as these can trigger MAT, as stated by the European Heart Journal 1, 2

Non-dihydropyridine calcium channel blockers are the preferred agents for rate control in COPD patients with MAT, with a Class IIa recommendation, according to the European Heart Journal and Circulation 1, 2, 3
Intravenous verapamil can terminate MAT in approximately 50% of patients and provides rate control in others, with a mean effective dose, as reported in Circulation 3
Intravenous metoprolol is an alternative that can achieve conversion to sinus rhythm in 68% of patients, but should be used with extreme caution in COPD patients, as stated by the European Heart Journal and Circulation 1, 2, 3

The European Heart Journal recommends never using non-selective β-blockers, sotalol, propafenone, or adenosine in MAT patients with obstructive lung disease, with a Class III recommendation 1, 2

Oral verapamil or diltiazem is recommended for rate control in patients with recurrent symptomatic MAT after hospital discharge, with a Class IIa recommendation, according to Circulation 3
Oral metoprolol is a reasonable alternative for maintenance, but should be used with caution, as stated by Circulation 3

MAT typically occurs in elderly patients with severe COPD and carries adverse prognostic implications during acute exacerbations, as reported by the European Heart Journal 1, 2
The mechanism of MAT likely involves triggered activity from delayed afterdepolarizations, which explains why cardioversion fails, according to Circulation 3
Both β-blockers and calcium channel blockers should be avoided in acute decompensated heart failure, as stated by Circulation 3
Small doses of β-1 selective blockers, such as bisoprolol, can be considered as alternatives for rate control, with a Class IIa recommendation, according to the European Heart Journal 1, 2

The American College of Cardiology defines Multifocal Atrial Tachycardia (MAT) as a rapid, irregular rhythm with at least 3 distinct morphologies of P waves on the surface ECG 4
Diagnostic criteria for MAT include atrial rate >100 bpm, distinct isoelectric period between P waves, and variable P-P, P-R, and R-R intervals 4
A 12-lead ECG is essential to distinguish MAT from atrial fibrillation, which can appear similar on physical examination or single-lead monitoring 4

MAT is commonly associated with underlying conditions including pulmonary disease, pulmonary hypertension, coronary disease, and valvular heart disease 4
Other precipitating factors for MAT include hypomagnesemia, theophylline therapy, hypokalemia, hypoxia, acidemia, and increased catecholamines 4, 5

The American College of Cardiology recommends addressing primary pulmonary, cardiac, or other systemic disease as the first step in managing MAT 6, 4
Correcting electrolyte abnormalities, particularly hypomagnesemia, is crucial in managing MAT 4, 5
Consider intravenous magnesium supplementation even in patients with normal magnesium levels 4
Discontinuing or adjusting theophylline therapy is recommended if applicable 4
Intravenous metoprolol can be useful for acute treatment of MAT (Class IIa recommendation) 6, 4
Intravenous verapamil is an alternative for acute treatment of MAT (Class IIa recommendation) 6, 4
Avoid cardioversion as it is not effective in MAT 6, 4
Oral metoprolol is reasonable for ongoing management in patients with recurrent symptomatic MAT (Class IIa recommendation) 6, 7
Oral verapamil or diltiazem is reasonable for ongoing management (Class IIa recommendation) 6, 4

Beta blockers should be used with caution in patients with pulmonary disease, particularly those with bronchospasm 6, 4
Calcium channel blockers should be avoided in patients with ventricular dysfunction, sinus node dysfunction, AV block, or acute decompensated heart failure 6, 4
Both beta blockers and calcium channel blockers should be avoided in hemodynamically unstable patients 6, 4
Monitor for hypotension, especially with verapamil administration 4