Tracing B was recorded two hours after the tracing A (on the previous page) and tracing C was recorded the next day. In tracing B, the atrial rate has slowed to 65 (the PP interval 0.8 seconds) and there is 1:1 conduction but with a prolonged PR interval (0.24 seconds). This suggests that the high grade AV block recorded in tracing A might have been rate dependent.
In tracing C, the atrial rate is again faster (the PP interval is now 0.68 seconds, a rate of 88) and there is again high grade AV block but there is now an occasional conducted beat. The beats labeled 1,3,5 and 7 are AV junctional escape beats from an AV junctional pacemaker having a rate of 46 but beats 2 and 6 are conducted with a PR interval of 0.26 seconds. This results in the shorter RR intervals (0.98 and 1.00 seconds) associated with these beats.