Multi focal atrial tachycardia (MAT)
MAT is characterized by a rhythm with at least three distinct P-wave morphologies with rates
typically between 100 and 150 beats/min.
Unlike atrial fibrillation, there are clear isoelectric intervals between P waves and the atrial
rate is slower.
The mechanism is likely triggered automaticity from multiple atrial foci.
It is usually encountered in patients with chronic pulmonary disease and acute
illness.
Therapy for MAT is directed at treating the underlying disease and correcting any metabolic
abnormalities.
Electrical cardioversion is ineffective.
The calcium channel blockers verapamil or diltiazem may slow the atrial and ventricular rate.
Patients with severe pulmonary disease often do not tolerate beta blocker therapy. MAT may
respond to amiodarone, but long-term therapy with this agent is usually avoided due to its
toxicities, particularly pulmonary fibrosis.
The associated risk of thromboembolism in MAT remains unclear but is not considered to be
the same as atrial fibrillation or atrial flutter.
Reference : Harrison's 21st edition
