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
Bachmann's bundle found that clamping the muscular bundle of fibers that connects the atria caused a significant conduction delay. The Bachman's bundle receives its blood supply from the sinoatrial nodal artery (right, left or both). Besides Bachmann's bundle, the other three conduction tracts that constitute the "atrial conduction system" are known as the anterior, middle, and posterior tracts, which run from the sinoatrial node to the atrioventricular node, converging in the region near the coronary sinus. "Atrial automaticity foci" are within the atrial conduction system. The concentration of converging conduction tracts near the coronary sinus results in considerable automaticity activity originating in