Figure 2.

Examples of organized atrial arrhythmias. A: Sudden onset and offset of regular narrow complex tachycardia. B: Episode of organized atrial arrhythmia showing abrupt offset and a peak ventricular rate greater than maximal age-predicted heart rate. Note the sinus pause at the termination of an episode suggestive of sinus node dysfunction. C: Initiation of this organized atrial arrhythmias starts with a wider QRS secondary to aberrant conduction. Clear p waves are seen during the tachycardia. D: Regular narrow complex tachycardia at a rate of 188 bpm in an 82-year-old patient with peak heart rate exceeding maximal age-predicted heart rate.