Rapid Review·Cardiovascular
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Arrhythmias: Supraventricular
T2High yieldMultifocal Atrial Tachycardia
Focus on
An elderly patient in a COPD exacerbation with an irregular narrow tachycardia and at least three different P-wave shapes. It looks like AF but is not: no cardioversion, no anticoagulation — treat the lungs, the oxygen and the electrolytes; verapamil or a beta blocker only if it persists.
Key takeaways
What it is and who gets it
Multifocal atrial tachycardia (MAT)
a supraventricular tachycardia from multiple ectopic atrial foci: rate over 100 with 3 or more P-wave shapes.Triggers
atrial conduction disturbances from right atrial enlargement, a catecholamine surge (sepsis) or electrolyte imbalance.Wandering pacemaker
the same picture at a normal rate.The classic patient
elderly (over 70) with an acute exacerbation of lung disease.- A chronic obstructive pulmonary disease (COPD) exacerbation is the most common association, then a heart failure exacerbation.
Other risk factors
hypokalemia, hypomagnesemia, sepsis.Clinical features and diagnosis
Often asymptomatic
unless the rate worsens an underlying condition such as heart failure.Electrocardiogram (ECG)
an irregularly irregular narrow-complex rhythm at about 150 to 250 with at least 3 different P-wave morphologies, as in the Recognize MAT on ECG.Management
Treat the cause first
it is usually self-limited.- Antibiotics, bronchodilators, steroids and non-invasive ventilation for the COPD exacerbation; replace electrolytes.
Atrioventricular (AV) nodal blockade
a beta blocker, verapamil or diltiazem, only for symptoms that persist despite that.A 76-year-old in a COPD exacerbation has an irregular narrow-complex tachycardia at 130 with P waves of four different shapes. What is the rhythm and the first-line treatment?
Multifocal atrial tachycardia. Treat the underlying cause (bronchodilators, steroids, antibiotics, non-invasive ventilation, electrolytes); AV nodal blockers only if symptoms persist.
How it's tested
A 74-year-old with COPD, wheezing and an oxygen saturation of 86%, heart rate 130 and irregular, ECG with P waves of several shapes: multifocal atrial tachycardia — oxygen, bronchodilators, steroids, magnesium; not cardioversion, not warfarin.
Same patient after the exacerbation improves, still at 120 with symptoms: verapamil (or diltiazem) — avoids bronchospasm.
What distinguishes it from AF on the strip: discrete P waves of at least three morphologies with an isoelectric baseline.
Which electrolyte to replete even if normal-range: magnesium.
Go deeper
Related Step 2 pages: Atrial Fibrillation, Approach to Tachyarrhythmias, Cor Pulmonale, Premature Atrial Complexes
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