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
Longitude of the ascending node it is not possible to tell which node is ascending and which is descending. In this case the orbital parameter which is recorded is the longitude of the node, Ω, which is the longitude of whichever node has a longitude between 0 and 180 degrees. In astrodynamics, the longitude of the ascending node can be calculated from the specific relative angular momentum vector h as follows: Here, n=<"n", "n", "n"> is a vector pointing towards the ascending node. The reference plane is assumed to be the "xy"-plane, and the origin of longitude is taken to be the positive "x"-axis. k