Multifocal atrial tachycardia (MAT) is a medical condition characterized by accelerated heart rate caused by the regular electric impulse generation in multiple atrial foci. There aren't many synonyms for MAT, but some terms describe the condition from different perspectives. For instance, MAT is called chaotic atrial tachycardia due to the irregularity in the conduction system. Other names for the condition include irritable atrial tachycardia, polyfocal atrial tachycardia, and polyauxialized sinus tachycardia. Though these terms might describe MAT differently, they refer to the same condition. MAT often occurs in older people and those with chronic obstructive pulmonary disease, heart disease, or pneumonia. Symptoms of MAT include palpitations, dizziness, shortness of breath, and chest discomfort.