- History of cardiac rhythm abnormalities or cardiac rhythm abnormalities identified in the 24-h Holter ECG recording including episodes of bradycardia (HR < 50 bpm) during waking hours and/or arrhythmic episodes; subjects with history or presence of ventricular rhythm disturbances (ventricular extra-systoles >100/24h, or higher grade), or supraventricular arrhythmias (other than occasional supraventricular ectopic beats with a maximum of 5 subsequent ectopic beats per event) or subjects with conduction disturbances (higher than AV-block grade 1) or bradycardia or tachycardia.