Description: Segment 1 Kirkler introduces the subject and shows photographs and tracings from early ECG apparatus. He then demonstrates how ECG tracings are unable to give detailed information about various important aspects of the major intervals, particularly the P-R interval. Kirkler shows how this is better seen on an intracardiac electrogram, he explains it in detail. Time start: 00:00:00:00 Time end: 00:05:38:14 Length: 00:05:38:14 Segment 2 Using diagrams and photographs to illustrate his points, Kirkler shows how intracardiac electrography is performed. We see the apparatus used in a hospital theatre and Kirkler presents and explains the findings in a series of diagrams. Time start: 00:05:38:14 Time end: 00:09:38:10 Length: 00:03:59:21 Segment 3 Kirkler continues to demonstrate the functions of intracardiac electrography. He shows, in particular, tracings from the His bundle and explains what aspects of heart activity they relate to. Time start: 00:09:38:10 Time end: 00:15:00:00 Length: 00:05:22:15 Segment 4 Kirkler focuses on congenital complete heart block, showing tracings of this on an intracardiac recording from the His bundle electrogram. He compares the details of this tracing with tracings of other forms of heart block. Kirkler then turns to focus on rhythm disorders, demonstrating through tracings how intracardiac electrography can refine the process of accurate diagnosis. Time start: 00:15:00:00 Time end: 00:21:00:15 Length: 00:06:00:15 Segment 6 Kirkler continues to demonstrate and illustrate ways in which intracardiac electrography is useful. He focuses on two conditions which would be hard to diagnose without the technique: paroxysmal sinus tachycardia and sinoatrial block, he analyses tracings from both of these conditions. Time start: 00:25:26:00 Time end: 00:33:01:20 Length: 00:07:36:20