Ventricular Fibrillation in Emergency Medicine Clinical Presentation

Updated: Dec 30, 2015
  • Author: Keith A Marill, MD; Chief Editor: Erik D Schraga, MD  more...
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Ventricular fibrillation (VF) often occurs without forewarning. The following symptoms, while not necessarily specific for sudden cardiac death or VF, may develop before any major cardiac event:

  • Chest pain and other angina equivalents

  • Dyspnea

  • Easy fatigue

  • Palpitations

  • Immediately preceding acute cardiac arrest, possible increase in heart rate, presence of premature ventricular contractions (PVCs), or period of VT



Physical examination findings may include no pulse or respiration as well as wide and chaotic QRS complexes on cardiac monitors.

Patients in cardiac arrest have no pulse. However, both lay rescuers and healthcare providers may have difficulty determining pulselessness. Current AHA guidelines do not recommend that lay rescuers check for a pulse. Healthcare providers should take no more than 10 seconds to check for a pulse. If no pulse is found, the provider should proceed with chest compressions.

Patients in cardiac arrest have absent or abnormal (gasping) respirations. Adults who are unresponsive or have been witnessed to collapse, and have absent or abnormal respirations are likely to be in cardiac arrest. AHA guidelines recommend activating the emergency response system (call 911) and initiating CPR.

Patients in cardiac arrest become unconscious.



Cardiac causes with structural heart disease include the following:

  • Myocardial ischemia or infarction due to coronary artery disease: Coronary atherosclerosis and its consequences are responsible for approximately 80% of sudden cardiac deaths in the United States.

  • Cardiomyopathy: Dilated and hypertrophic cardiomyopathies are the second most important cardiac causes of sudden death. The degree of functional and physiologic left ventricular impairment is correlated with the risk of sudden death: dilated, hypertrophic, or arrhythmogenic right ventricular cardiomyopathy or dysplasia.

  • Pericardial tamponade

  • Congenital heart disease

Cardiac causes in the absence of structural heart disease include the following

  • Catecholaminergic polymorphic ventricular tachycardia and right ventricular outflow tract tachycardia

  • Mechanical (commotio cordis) [7] or electrical accidents

  • Preexcitation (including Wolff-Parkinson-White syndrome)

  • Heart block

  • Drug-induced QT prolongation with torsades de pointes

  • Channelopathies: long QT syndrome, short QT syndrome, or Brugada syndrome

Noncardiac respiratory causes include the following:

Metabolic or toxic causes include the following:

  • Electrolyte disturbances and acidosis

  • Medications or drug ingestion

  • Environmental poisoning

  • Sepsis

Neurologic causes include the following:

  • Seizure

  • Cerebrovascular accident - Intracranial hemorrhage or ischemic stroke