• This form of wandering atrial pacemaker is associated with a ventricular response greater than 100 bpm.
• MAT may be confused with atrial fibrillation (A-fib); however, MAT has a visible P wave.

Rate: Fast (greater than 100 bpm)

Rhythm: Irregular

P Waves: At least three different forms, determined by the focus in the atria

PR Interval: Variable; determined by focus

QRS: Normal (0.06–0.10 sec)

Clinical Tip: MAT is commonly seen in patients with chronic obstructive pulmonary disease (COPD) but may also occur in those with an acute myocardial infarction (MI).