Medical uses
Immunoglobulin therapy is used in a variety of conditions, many of which involve decreased or abolished antibody production capabilities, which range from a complete absence of multiple types of antibodies, to IgG subclass deficiencies (usually involving IgG2 or IgG3), to other disorders in which antibodies are within a normal quantitative range, but lacking in quality – unable to respond to antigens as they normally should – resulting in an increased rate or increased severity of infections. In these situations, immunoglobulin infusions confer passive resistance to infection on their recipients by increasing the quantity/quality of IgG they possess. Immunoglobulin therapy is also used for a number of other conditions, including in many autoimmune disorders such as dermatomyositis in an attempt to decrease the severity of symptoms. Immunoglobulin therapy is also used in some treatment protocols for secondary immunodeficiencies  such as human immunodeficiency virus (HIV), some autoimmune disorders (such as immune thrombocytopenia and Kawasaki disease), some neurological diseases (multifocal motor neuropathy, stiff person syndrome, multiple sclerosis and myasthenia gravis) some acute infections and some complications of organ transplantation.Immunoglobulin therapy is especially useful in some acute infection cases such as pediatric HIV infection and is also considered the standard of treatment for some autoimmune disorders such as Guillain–Barré syndrome. The high demand which coupled with the difficulty of producing immunoglobulin in large quantities has resulted in increasing global shortages, usage limitations and rationing of immunoglobulin.
Bundle of Kent
The bundle of Kent is an abnormal extra or accessory conduction pathway between the atria and ventricles that is present in a small percentage (between 0.1 and 0.3%) of the general population. This pathway may communicate between the left atrium and the left ventricle, in which case it is termed a "type A pre-excitation", or between the right atrium and the right ventricle, in which case it is termed a "type B pre-excitation" in old, currently abandoned classification. Problems arise when this pathway creates an electrical circuit that bypasses the AV node. The AV node is capable of slowing the rate of conduction of electrical impulses to the ventricles, whereas the bundle of Kent lacks this capability. When an aberrant electrical connection is made via the bundle of Kent, tachydysrhythmias may therefore result. Diagnosis
WPW is commonly diagnosed on the basis of the electrocardiogram in an asymptomatic individual. In this case, it is manifested as a delta wave, which is a slurred upstroke in the QRS complex that is associated with a short PR interval. The short PR interval and slurring of the QRS complex are reflective of the impulse making it to the ventricles early (via the accessory pathway) without the usual delay experienced in the AV node.If a person with WPW experiences episodes of atrial fibrillation, the ECG shows a rapid polymorphic wide-complex tachycardia (without torsades de pointes).