Ventricular fibrillation is one type of arrhythmia that can be deadly. It occurs when the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in your heart (the ventricles) to quiver uselessly instead of pumping blood. Without an effective heartbeat, blood pressure plummets, cutting off blood supply to your vital organs.
In the ABO system, (and Rhesus D system) all blood belongs to one of four major groups: A+/â, B+/â, AB+/â, or O+/â. The presence (+) or absence (â) of the RhD (Rhesus D) antigen is indicated by the plus or minus following the ABO type. But there are more than two hundred minor blood groups that can complicate blood transfusions. These are known as rare blood types.
Blood groups. Introduction. There are four main blood groups (types of blood): A, B, AB and O. Your blood group is determined by the genes you inherit from your parents. Each group can be either RhD positive or RhD negative, which means your blood group can be one of the eight types shown below (see the Rh system).