Atrial tachycardia and other ectopic atrial rhythms occur when a site ... Brief atrial tachycardia is seen very commonly on ambulatory ECG monitoring in the elderly and is frequently asymptomatic.

T wave alternans refers to the variation of the T wave amplitude on an ECG on a beat-to-beat basis. Having significant T wave alternans is thought to increase the risk of ventricular arrhythmias ...