View source for Fibrillation

'''Fibrillation''' is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with regards to the [[heart]]. 

==Cardiology==
There are two major classes of cardiac fibrillation: [[atrial fibrillation]] and [[ventricular fibrillation]].

* [[Atrial fibrillation]] can be a chronic condition, usually treated with anticoagulation and sometimes with [[cardioversion| conversion]] to [[cardiac pacemaker| normal sinus rhythm]]. This originates in the Atrium and an electrical impulse is "quivering" (fibrillation). An electrical pulse is given off, but is not the optimal way of sending an electrical pulse.

* [[Ventricular fibrillation]] is rapidly fatal if not reversed by [[defibrillation]]. No electrical impulse is given off in this form of dysrhythmia. 

Fibrillation may sometimes be used after heart surgery to stop the heart from beating while any minor leaks are stitched up.

==Musculoskeletal==
Fibrillation also occurs with individual skeletal muscle fibers.<ref>{{DorlandsDict|three/000039912|fibrillation}}</ref> This happens when muscle ﬁbers lose contact with their innervating axon producing a spontaneous action potential, "fibrillation potential" that results in the muscle fiber's contraction. These contractions are not visible under the skin and are detectable through needle [[electromyography]] (EMG) and ultrasound.<ref> Pillen S, Nienhuis M, van Dijk JP, Arts IM, van Alfen N, Zwarts MJ. (2009). Muscles alive: ultrasound detects fibrillations.  Clin Neurophysiol. 120(5):932-6.  PMID 19356976 {{doi|10.1016/j.clinph.2009.01.016}}</ref>  Fibrillations do not occur in healthy individuals. They are a major symptom in acute and severe  peripheral nerve disorders, in myopathies in which muscle ﬁbers are split or inﬂammed, and [[lower motor neuron lesion]]s.  

They contrast with [[fasciculations]] that are ''visible'' spontaneous contractions involving ''small groups'' of muscle fibers.  Also, fasciculation does not necessarily denote pathology, as does fibrillation, although it can be seen in lower motor neuron lesions as well.

==References==
{{reflist}}

{{medicine-stub}}
{{Heart diseases}}
{{Nervous and musculoskeletal system symptoms and signs}}
[[Category:Cardiology]]

[[ar:رجفان]]
[[da:Hjerteflimmer]]
[[de:Fibrillation]]
[[es:Fibrilación]]
[[uk:Фібриляція]]
[[ur:رجفان]]
[[Category:2Fix]]