• A deadly heart rhythm in which the ventricles contract independently of the atria and in a chaotic manner.
  Harvard Dictionary of Health Terms
  Harvard Medical Publishing, 2011
• A disorder characterized by an electrocardiographic finding of a rapid grossly irregular ventricular rhythm with marked variability in QRS cycle length, morphology, and amplitude. The rate is typically greater than 300 bpm. (CDISC)
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• An irregular heart rhythm, usually associated with a rapid rate, that is caused by abnormal electrical activity within the ventricles.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021
• Arrhythmia characterized by chaotic contractions of the ventricular muscle.
  U.S. FDA Glossary
  U.S. Food & Drug Administration, 2021
• Arrhythmia characterized by fibrillary contractions of the ventricular muscle due to rapid repetitive excitation of myocardial fibers without coordinated contraction of the ventricle.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Uncontrolled contractions of muscles fibers in the left ventricle not producing contraction of the left ventricle. Ventricular fibrillation usually begins with a ventricular premature contraction and a short run of rapid ventricular tachycardia degenerating into uncoordinating ventricular fibrillations.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2021
• Ventricular Fibrillation is characterized by rapid, usually more than 300 bpm (cycle length: 180 ms or less), grossly irregular ventricular rhythm with marked variability in QRS cycle length, morphology, and amplitude.
  CDISC Terminology
  Clinical Data Interchange Standards Consortium (CDISC), 2021
• A disorder characterized by a dysrhythmia without discernible QRS complexes due to rapid repetitive excitation of myocardial fibers without coordinated contraction of the ventricles.
  Common Terminology Criteria for Adverse Events
  U.S. National Institutes of Health, 2021
• Ventricular fibrillation causes uncoordinated quivering of the ventricle with no useful contractions. It causes immediate syncope and death within minutes. Treatment is with cardiopulmonary resuscitation, including immediate defibrillation.
  Merck Manuals
  Merck & Co., Inc., 2020
• Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia in which the coordinated contraction of the ventricular myocardium is replaced by high-frequency, disorganized excitation, resulting in failure of the heart to pump blood. VF is the most commonly identified arrhythmia in cardiac arrest patients.
  Medscape
  WebMD, 2019
• Ventricular fibrillation is a heart rhythm problem that 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. Sometimes triggered by a heart attack, ventricular fibrillation causes your blood pressure to plummet,...
  Mayo Clinic
  Mayo Foundation for Medical Education and Research
• Ventricular fibrillation, a type of arrhythmia (abnormal heart rhythm) characterized by the irregular and uncoordinated contraction of the muscle fibres of the ventricles, the lower chambers of the heart. Since ventricular fibrillation completely prevents the heart from functioning as a pump, it...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020