Atrial premature beats (APBs) are slightly less frequent than ventricular premature beats (VPBs) but much more frequent than
supraventricular premature beats arising in the atrioventricular (AV) junction. Often, APBs are not associated with heart
disease. In up to 64% of healthy young individuals, some APBs are found in an ambulatory electrocardiogram (Holter ECG), and
in most cases without symptoms.