Does fibrillation affect how the heart pumps blood?

Answer 1

Fibrillation is when all the cells of the heart start conrtacting of their own accord, ie no longer under the control of the SA node. This can happen because the Membrane Potentials of the cardiac cells are very unstable and a slight concentration change in certain ions will cause the cells to start Depolarising and contracting. This means that the heart is not contracting as one smooth mution but in small section at a time giving it an appearance often reffered to as like "a bag of worms". Fibrulation ot the heard causes an Electrocardiogram wave to look completely random with no pettern just a squigly line. The consequence of fibrulation is that, without the normal smooth contraction as one organ, there is no decrease in the size of the heart Chamber thus no blood is forced out into the circulation. In short the the effect of fibrulation is a that blood stops being pumped around the body. The way this is corrected is by us of a Defirulator. These are the machines with the pads that send electric pulses into the body (you've possibly seen them on ER or some other medical drama). How these work is not, as some believe, to kickstart the hear at all. The opposite infact, they stop the heart, momentarily, giving the SA node another chance to take control. After a while though there is not point continuin as the patient will have spent to long not receiving nutrients to the brain and will have died.