Accelerated idioventricular rhythm injury. AIVR is generally considered to be a benign abnormal heart rhythm. It is typically temporary and does not require treatment. In the human heart the sinoatrial node is located at the top of the right atrium. The sinoatrial node is the first area of the heart to depolarize and to generate the action potential that leads to depolarization of the rest of the myocardium. Sinoatrial depolarization and subsequent propagation of the electrical impulse suppress the action of the lower natural pacemakers of the heart, which have slower intrinsic rates. The accelerated idioventricular rhythm occurs when depolarization rate of a
Sinoatrial node the 3 phases of a sinoatrial node action potential. In the ventricular action potential, there are 5 phases (labelled 0-4), however pacemaker action potentials don’t have an obvious phase 1 or 2. Phase 4 This phase is also known as the pacemaker potential. Immediately following an action potential, when the membrane potential is very negative (it is hyperpolarised) the voltage slowly begins to increase. This is initially due to the closing of potassium channels, which reduces the flow of potassium ions (I) out of the cell (see phase 3, below). Alongside the deactivation of the potassium channels, channels known as