Bachmann's bundle that area. The normal cardiac rhythm originates in the sinoatrial node, which is located in the right atrium near the superior vena cava. From there, the electrical activation spreads throughout the right atrium. There are at least four different locations where the activation can pass to the left atrium. Apart from Bachmann's bundle these are the anterior interatrial septum, posterior interatrial septum, and the coronary sinus. Because it originates close to the sinoatrial node and consists of long parallel fibers, Bachmann's bundle is, during sinus rhythm, the first of these connections to activate the left atrium. Bachmann's bundle In the
Sinoatrial block block looks very similar to a sinus arrest. However, a sinus arrest is caused by a failure to form impulses. A third degree block is caused by failure to conduct them. The rhythm is irregular and either normal or slow. It is followed by a long pause that is not a multiple of the P-R interval. The pause ends with a P wave, instead of a junctional escape beat the way a sinus arrest would. Emergency treatment consists of administration of atropine sulfate or transcutaneous pacing. Sinoatrial block A sinoatrial block is a disorder in the normal rhythm of the