The RR interval is the distance between two ventricular electrical activities on the ECG and reflects whether the electrical activity of the ventricles is regular or not. Normally, the R-wave appears at the highest point of each beat on the ECG. A high RR interval is indicative of bradycardia, which is considered to be a bradyarrhythmia, such as sinus bradycardia, atrioventricular block, fast-slow syndrome, and sinus arrest, and is also common in the elderly. If the RR interval is too high on the ECG due to the above mentioned bradyarrhythmias, then the possible symptoms are palpitations, dizziness, fainting, blackout, and transient loss of consciousness. Symptoms may occur when the RR interval is higher than 2000 ms, and syncope may occur when it is higher than 3000 ms, which is an indication for implantation of a permanent pacemaker.