Sinoatrial node produced an increased heart rate whereas an inferior shift (i.e. the cell producing the fastest action potential within the SA node is further down than previously) produced a decreased heart rate. Sinus node dysfunction describes an irregular heartbeat caused by faulty electrical signals of the heart. When the heart's sinoatrial node is defective, the heart’s rhythms become abnormal – typically too slow or exhibiting pauses in its function or a combination, and very rarely faster than normal. Blockage of the arterial blood supply to the SA node (most commonly due to a myocardial infarction or progressive coronary artery disease) can
Sentinel node list, can be simplified remarkably using a sentinel node to demarcate the beginning and end of the list. Following is a Python implementation of a circular doubly-linked list: Notice how the codice_13 method takes the node that will be displaced by the new node in the parameter codice_14. For appending to the left, this is the head of a non-empty list, while for appending to right, it is the tail. But because of how the linkage is setup to refer back to the sentinel, the code just works for empty lists as well, where codice_14 will be the sentinel node.