fibrillation

1. The forming of fibers.
2. 1. Fine, rapid twitching of individual muscle fibers with little or no movement of the muscle as a whole.
   2. Rapid uncoordinated twitching movements that replace the normal rhythmic contraction of the heart and may cause a lack of circulation and pulse.

Non-rhythmic and mechanically ineffective contractile activity in the heart muscle, associated with disordered electrical activity. Atrial fibrillation is not uncommon, and not in itself a serious threat: the heart can function without effective contraction of the atria, because the main pumps (ventricles) continue to beat effectively (though not regularly). But ventricular fibrillation stops the pump and is fatal, unless it can be promptly reversed.

— Stuart Judge

See defibrillator; heart; pacemaker.

A local quivering of muscle fibers.

Rapid and irregular beating of the heart, or quivering of cardiac fibres, causing inefficient emptying of the heart chambers. Fibrillation in the ventricles causes cardiac arrest.

1. a small, local, involuntary, muscular contraction, due to spontaneous activation of single muscle cells or muscle fibers.
2. the quality of being made up of fibrils.
3. the initial degenerative changes in osteoarthritis, marked by softening of the articular cartilage and development of vertical clefts between groups of cartilage cells.

• atrial f. — a cardiac arrhythmia marked by rapid randomized contractions of the atrial myocardium, causing a totally irregular, often rapid, ventricular rate. There is no synchronous atrial contraction and the ventricles beat irregularly. The heartbeat is irregular, the pulse is irregular in rhythm and amplitude. Common in the horse; an affected animal can still race but the performance is poor. Occurs in dogs in association with cardiac disease, particularly idiopathic congestive cardiomyopathy, and electrolyte disturbances.
• ventricular f. — a cardiac arrhythmia marked by fibrillatory contractions of the ventricular muscle due to rapid repetitive excitation of myocardial fibers without coordinated ventricular contraction. Ventricular fibrillation is a frequent cause of cardiac arrest. An apparatus called a defibrillator sometimes is used to alleviate fibrillation. The defibrillator delivers an electric shock to the heart muscle, depolarizing the muscle and ending the irregular contractions. The heart is then able to resume normal, regular contractions.

Fibrillation is the rapid, irregular, and unsynchronized contraction of muscle fibers. An important occurrence is with 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 conversion to 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.^[1] 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.^[2] 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 lesions.

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

1. ^ fibrillation at Dorland's Medical Dictionary
2. ^ 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

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v • d • e Cardiovascular disease: heart disease · Circulatory system pathology (I00-I52, 390-429) Ischaemic CD/CHD CAD · Coronary thrombosis · Coronary vasospasm · Coronary artery aneurysm Active ischemia Angina pectoris (Prinzmetal's angina, Stable angina) · Acute coronary (Unstable angina, Myocardial infarction / heart attack) Sequelae hours (Myocardial stunning, Hibernating myocardium) · days (Myocardial rupture) · weeks (Aneurysm of heart, Dressler's syndrome) Layers Pericardium Pericarditis (Acute, Chronic/Constrictive) · Pericardial effusion (Hemopericardium, Cardiac tamponade) Myocardium Myocarditis (Chagas disease) Cardiomyopathy: Dilated (Alcoholic) · Hypertrophic · Restrictive (Loeffler endocarditis, Cardiac amyloidosis, Endocardial fibroelastosis) Arrhythmogenic right ventricular dysplasia Endocardium/ valves Endocarditis Infective endocarditis (Subacute bacterial endocarditis) · noninfective endocarditis (Nonbacterial thrombotic endocarditis, Libman-Sacks endocarditis) Valves mitral (regurgitation, prolapse, stenosis) · aortic (stenosis, insufficiency) · tricuspid (stenosis, insufficiency) · pulmonary (stenosis, insufficiency) Conduction/ arrhythmia Bradycardia Sinus bradycardia · Sick sinus syndrome Heart block: Sinoatrial · AV (1°, 2°, 3°) · Intraventricular (Bundle branch/Right/Left, Left anterior fascicular/Left posterior fascicular, Bifascicular/Trifascicular) · Adams-Stokes syndrome Tachycardia (paroxysmal and sinus) Supraventricular Atrial (Multifocal) · Junctional (AV nodal reentrant, Junctional ectopic) Ventricular Torsades de pointes · Catecholaminergic polymorphic · Accelerated idioventricular rhythm Premature contraction Atrial · Ventricular Pre-excitation syndrome Wolff-Parkinson-White · Lown-Ganong-Levine Flutter/fibrillation Atrial flutter · Ventricular flutter · Atrial fibrillation (Familial) · Ventricular fibrillation Pacemaker Wandering pacemaker · Ectopic pacemaker/Ectopic beat · Parasystole · Multifocal atrial tachycardia · Pacemaker syndrome Long QT syndrome Romano-Ward syndrome · Andersen-Tawil syndrome · Jervell and Lange-Nielsen syndrome Cardiac arrest Sudden cardiac death · Asystole · Pulseless electrical activity · Sinoatrial arrest Other/ungrouped hexaxial reference system (Right axis deviation, Left axis deviation) · QT (Short QT syndrome) · T (T wave alternans) · ST (Osborn wave, ST elevation, ST depression) Cardiomegaly Ventricular hypertrophy (Left, Right/Cor pulmonale) · Atrial enlargement (Left, Right) Other Cardiac fibrosis · Heart failure (Cardiac asthma) · Rheumatic fever heart navs: non-congenital diseases, congenital, neoplasia

v • d • e Symptoms and signs: nervous and musculoskeletal systems (R25-R29, 781) Abnormal involuntary movements (see also movement disorders) Neuromuscular manifestation: Spasm (Trismus) · Fasciculation · Fibrillation · Myokymia · Cramp  · Restless legs syndrome Dyskinesia: Athetosis · Tremor Gait abnormality Scissor gait · Antalgic gait · Cerebellar ataxia · Festinating gait · Pigeon gait · Propulsive gait · Steppage gait · Stomping gait · Spastic gait · Myopathic gait · Magnetic gait · Trendelenburg gait Lack of coordination Dyskinesia: Ataxia (Cerebellar ataxia/Dysmetria, Sensory ataxia) Dysdiadochokinesia · Asterixis Other Tetany · Meningism · Hyperreflexia Abnormal posturing: Opisthotonus Perceptual disorder: Hemispatial neglect see also eponymous medical signs for nervous system, eponymous medical signs for musculoskeletal system

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