What is Ventricular Fibrillation?

It is most dangerous cardiac arrhythmia as it produces sudden death. Sudden cardiac death is defined as non-traumatic unexpected death in clinically stable and well patients who die within one hour after the onset of symptoms.



  1. Ischaemic heart disease particularly during acute myocardial infarction.
  2. Drugs-Digitalis, Quinidine, Adrenaline, Phenonthiazines, Cyclopropane anaesthesia, Bretylium.
  3. Hypothermia.
  4. Rheumatic Myocarditis.
  5. Cardiac operations.
  6. Any anoxic condition.
  7. Electrolyte imbalance like hypo- and hyperkalaemia and hypercalcaemia.
  8. Electrocution.
  9. Rarely in association with complete AV block, long QT syndrome etc.
  10. Non-ischaemic cardiomyopathy and infiltration diseases.
  11. Infectious diseases like viral myocarditis, Chagas disease, lyme disease.
  12. Congenital cardiac defects such as myopathy, arrhythmogenic right ventricular dysplasia.
  13. Inflammatory diseases affecting myocardium SLE, Rheumatoid arthritis. hypertrophic cardio-
  14. Surgical repair of congenital heart disease.
  15. Cardiac malignancy-primary and secondary.
  16. Aortic stenosis, pulmonary stenosis, primary pulmonary hypertension.
  17. Congenital cyanotic heart disease.
  18. Mitral valve prolapse.
  19. Cardiac conduction defects.

Clinically pulse and heart sounds are absent and patient develops shock with rapid coma. Stokes Adams attack may also develop.


Use of defibrillators under DC counter shock is the treatment of choice. When facilities are not available external cardiac massage with mouth to mouth breathing should be done Common drugs, e.g. Quinidine, Procainamide should be avoided. Treatment should be adopted to restore circulation by external cardiac massage together with mouth to mouth breathing. Difibrillation is done with 400 J and if necessary it can be repeated. Acidosis is corrected by efficient ventillation. When severe acidosis develops Inj. Sodium bicarbonate 44 mEq is given IV. After difibrillation antiarrhythmic drug e.g. Inj. Lidocaine 1-4 mg per minute by IV may be started.