What are the defining characteristics of Multifocal Atrial Tachycardia?

Multifocal Atrial Tachycardia (MAT) is characterized by an irregular rhythm with a heart rate typically exceeding 100 beats per minute. One of the hallmark features of MAT is the presence of three or more different morphologies of P waves, signaling that multiple atrial sites are responsible for the impulses. This variation in P wave morphology reflects the different origins of atrial depolarization, which is a critical aspect in distinguishing MAT from other atrial arrhythmias.

Understanding the rhythm's irregularity and the diverse P wave shapes is essential for accurate diagnosis and management. In contrast, the other options either describe rhythms that are regular or P wave appearances that do not meet the criteria for the multifocal nature of MAT. The presence of one P wave morphology or a regular rhythm aligns more with other types of atrial tachycardia or other rhythm disturbances, which makes them unsuitable for describing MAT.