A rarely encountered type of group beating is that which occurs when there are escape beat in association with bradycardia.
This ECG is from a 69 year old male with severe congestive heart failure. It shows 2:1 AV block with group beating caused by a ventricular escape beat. The initial beat of each pair is the wide complex ventricular escape beat. It is followed by a conducted sinus beat with a PR interval of 0.20 seconds. This beat is then followed by the non-conducted sinus P wave. Note also that there is a P wave that is coincident with or occurs just after the onset of the escape beat and is obscured by it. This P wave is unable to conduct because of the escape beat.