Description: Segment 1 Children are seen playing in a playground, and the narrator says that around half of all children will have a heart murmur at some point. Most of these are completely 'innocent' or benign, but some are congenital and due to an atrial septal defect. However, there are often no symptoms of any heart defect. A young boy is examined by a doctor. The doctor listens to his heartbeat closely. Animated drawings show the movement of the heart beating, and the narrator discusses the movement of the heart in great detail. The sound of the heart is heard, and the narrator explains how this sound can be an indicator of a heart defect. Time start: 00:00:00:00 Time end: 00:07:43:24 Length: 00:07:43:24 Segment 2 Details of a heart murmur heard in the pulmonary area are given. A phonocardiogram shows the heart murmur. Characteristics of 'innocent' heart murmurs are given, and the physical signs between innocent and congenital murmurs are discussed. The patient has a chest x-ray and electrocardiogram to confirm that his murmur is not congenital. The embryology and pathology of the atrial septal defect is discussed using animated drawings. The narrator describes the development of a heart with an atrial septal defect in a foetus. The defect is due to the development of a shunt in the heart. Time start: 00:07:43:24 Time end: 00:13:56:03 Length: 00:06:12:04 Segment 3 A diagram of an atrial septal defect is shown, as well as one of the blood circulating in the heart. The dangers of the defect are listed. A young girl is seen having a routine examination. She has no symptoms of heart disease, yet she has an atrial septal defect. The left side of her chest bulges slightly, and this is a suggestion that she may have a congenital heart disease. The doctor listens to her heart. An animated diagram shows the flow of blood through the defect. The sound of her heartbeat also suggests a heart murmur, and it is the same in different postures. Time start: 00:13:56:03 Time end: 00:22:23:15 Length: 00:08:27:12 Segment 4 The narrator describes what is causing the murmur, and an animated diagram shows what is causing the abnormal heartbeat sound. The patient has an electrocardiography and a chest x-ray. The x-ray shows cardiac enlargement. The enlarged right atrium is shown. A cardiac catheterisation is peformed a catheter is introduced into the patient's arm vein and passed through to the heart to determine the pressure in the heart chambers and find evidence of a shunt in the heart. The results of the catheter test are discussed using an animated diagram. Time start: 00:22:23:15 Time end: 00:30:10:02 Length: 00:07:46:12