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The Heart - Part 2:

The heart’s electrical system consists of three parts of specialised myocardium - the sino-atrial (SA) node, the atrioventricular (AV) node and the bundle of His network (Tortora and Grabowski, 2002) (Fig 1). The starting point of the cardiac electrical cycle is the SA node. This is the heart’s natural/dominant pacemaker, which can create impulses at 60-100 beats per minute. Its ability to spontaneously generate and discharge an electrical impulse is called automaticity.

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