SINGLE-CHAMBER ATRIAL PACEMARKER (AAI pacemaker)
Single lead may be placed in the right atrium when an atrial dysrhythmia due to sinoatrial node dysfunction or an aberrant additional sinoatrial node pacemaker focus is present. In this case, the conduction tissues are normal; once the impulses are properly generated, they can travel unimpeded to the ventricles. Medical practice, however, has shifted to predominant implantation of dual chamber pacemaker (DDD) even in these cases to prevent atrioventricular conduction disturbances that could develop in the future.
On the lateral view, the right atrial lead has a “J-shaped” appearance entering the right atrium and then curving upward and anteriorly to its proper position in the right atrial appendage.
Links to pacemaker codes: