Subject search terms: Atrial arrhythmias, Atrial fibrillation, Atrial flutter, Extrasystole, Bradycardia, Electrocardiography, Tachycardia, Ventricular Fibrillation, Ventricular Tachycardia; Keyword search terms: Premature atrial contractions, premature ventricular contractions, Sinus bradycardia, Sinus rhythm, Sinus tachycardia, Supraventricular Tachycardia