fibrillation

Examples of fibrillation in the following topics:

• Arrhythmia

  • Arrhythmias - fibrillation: When an entire chamber of the heart is involved in a multiple micro-reentry circuits and, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation.
  • Fibrillation can affect the atrium (atrial fibrillation) or the ventricle (ventricular fibrillation); ventricular fibrillation is imminently life-threatening.
  • Atrial fibrillation affects the upper chambers of the heart, known as the atria.
  • If left untreated, ventricular fibrillation (VF, or V-fib) can lead to death within minutes.
  • It is typically not a stable rhythm, and frequently degenerates into atrial fibrillation (AF).

• Prions

  • Amyloid aggregates are fibrils, growing at their ends, and replicating when breakage causes two growing ends to become four growing ends.
  • An alternative model assumes that PrPSc exists only as fibrils , and that fibril ends bind PrPC and convert it into PrPSc.
  • If this were all, then the quantity of prions would increase linearly, forming ever longer fibrils.
  • This can be explained by taking into account fibril breakage.
  • A mathematical solution for the exponential growth rate resulting from the combination of fibril growth and fibril breakage has been found.

• Structural Elements of Connective Tissue

  • Collagen, in the form of elongated fibrils, is mostly found in fibrous tissues such as tendons, ligaments, and skin and is also abundant in cornea, cartilage, bone, blood vessels, the gut, and intervertebral discs.
  • The tropocollagen or collagen molecule is a subunit of larger collagen aggregates such as fibrils.
  • Collagen fibrils/aggregates are arranged in different combinations and concentrations in various tissues to provide varying tissue properties.
  • The tropocollagen or collagen molecule is a subunit of larger collagen aggregates such as fibrils.

• Electrocardiogram and Correlation of ECG Waves with Systole

  • A missing P wave indicates atrial fibrillation, a cardiac arrhythmia in which the heart beats irregularly, preventing efficient ventricular diastole.
  • When ECG output shows no identifiable P waves, QRS complexes, or T waves, it imdicates ventricular fibrillation, a severe arrhythmia.
  • During ventricular fibrillation, the heart beats extremely fast and irregularly and can no longer pump blood, acting as a mass of quivering, disorganized muscle movements.
  • Ventricular fibrillation will cause sudden cardiac death within minutes unless electrical resuscitation (with an AED) is performed immediately.

• Hemidesmosomes

  • Together with the anchoring fibrils and anchoring filaments, these are collectively termed the HD-stable adhesion complex or HD-anchoring filament complex.
  • Beneath the lamina densa, loop-structured, cross-banded anchoring fibrils extend more than 300 nm beneath the basement membrane within the papillary dermis.

• Basement Membranes and Diseases

  • The lamina reticularis is attached to the basal lamina with anchoring fibrils (type VII collagen fibers ) and microfibrils (fibrillin).
  • The electron-dense lamina densa membrane is about 30–70 nanometers in thickness, and consists of an underlying network of reticular collagen (type IV) fibrils (fibroblast precursors) which average 30 nanometers in diameter and 0.1–2 micrometers in thickness.

• Cerebrovascular Accident

  • Risk factors for stroke include old age, hypertension (high blood pressure), previous stroke or transient ischemic attack (TIA), diabetes, high cholesterol, cigarette smoking, and atrial fibrillation.
  • The most important modifiable risk factors for stroke are high blood pressure and atrial fibrillation (although magnitude of this effect is small).

• Transient Ischemic Attacks

  • This usually arises from a dislodged atherosclerotic plaque in one of the carotid arteries or from a thrombus (i.e. a blood clot) in the heart because of atrial fibrillation .
  • TIA is related to other medical conditions such as hypertension, heart disease (especially atrial fibrillation), migraine, cigarette smoking, hypercholesterolemia, and diabetes mellitus.

• Humans and Electric Hazards

  • The current may, if it is high enough, cause tissue damage or fibrillation, which leads to cardiac arrest. 60 mA of AC (rms, 60 Hz) or 300-500 mA of DC can cause fibrillation.The potential severity of the shock depends on paths through the body that the currents take.
  • Currents of only 10 µA can be sufficient to cause fibrillation in this case.

• Anticoagulants

  • These anticoagulants are used to treat patients with deep-vein thrombosis (DVT), pulmonary embolism (PE), atrial fibrillation (AF), and mechanical prosthetic heart valves.