Accelerated idioventricular rhythm is a ventricular rhythm with a rate of between 40 and 120 beats per minute. Idioventricular means “relating to or affecting the cardiac ventricle alone” and refers to any ectopic ventricular arrhythmia. Accelerated idioventricular arrhythmias are distinguished from ventricular rhythms with rates less than 40 (ventricular escape) and those faster than 120 (ventricular tachycardia). Though some other references limit to between 60 and 100 beats per minute. It is also referred to as AIVR and "slow ventricular tachycardia." It can be present at birth. However, it is more commonly associated with reperfusion after myocardial injury. AIVR is generally considered to be a benign abnormal heart rhythm. It is typically temporary and does not require treatment. Pathophysiology
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 the 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 normally suppressed focus increases to above that of the "higher order" focuses (the sinoatrial node and the atrioventricular node). This most commonly occurs in the setting of a sinus bradycardia.Accelerated idioventricular rhythm is the most common reperfusion arrhythmia in humans.
Sympathomimetics such as phenylpropanolamine, methylphenidate, and others are also implicated.In pediatric patients varicella inflammation may be followed by vasculitis of intracranial vessels. This condition is called post varicella angiopathy and this may be responsible for arterial ischaemic strokes in children.Several of these vasculitides are associated with antineutrophil cytoplasmic antibodies. These are:

Granulomatosis with polyangiitis
Eosinophilic granulomatosis with polyangiitis
Microscopic polyangiitis

Diagnosis
Laboratory tests of blood or body fluids are performed for patients with active vasculitis. Their results will generally show signs of inflammation in the body, such as increased erythrocyte sedimentation rate (ESR), elevated C-reactive protein (CRP), anemia, increased white blood cell count and eosinophilia. Other possible findings are elevated antineutrophil cytoplasmic antibody (ANCA) levels and hematuria. Other organ functional tests may be abnormal. Specific abnormalities depend on the degree of various organs involvement. A brain SPECT can show decreased blood flow to the brain and brain damage. The definite diagnosis of vasculitis is established after a biopsy of involved organ or tissue, such as skin, sinuses, lung, nerve, brain, and kidney. The biopsy elucidates the pattern of blood vessel inflammation.Some types of vasculitis display leukocytoclasis, which is vascular damage caused by nuclear debris from infiltrating neutrophils. It typically presents as palpable purpura. Conditions with leucocytoclasis mainly include hypersensitivity vasculitis (also called leukocytoclastic vasculitis) and cutaneous small-vessel vasculitis (also called cutaneous leukocytoclastic angiitis).An alternative to biopsy can be an angiogram (x-ray test of the blood vessels). It can demonstrate characteristic patterns of inflammation in affected blood vessels.