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 delayed or blocked on the way to the atria, thus delaying the atrial beat. (An AV block, occurs in the AV node and delays ventricular depolarisation). SA blocks are categorized into three classes based on the length of the delay. Sinoatrial blocks are typically well-tolerated. They are not as serious as an AV block and most often do not require treatment. In some people, they can cause fainting, altered mental status, chest pain, hypoperfusion, and signs of shock. They can also lead to cessation of the SA node and more serious dysrhythmias. In a first degree sinoatrial block, there is