The heart is an organ composed of four chambers: two atria and two ventricles, located on the left and right sides.
The ventricles, which are involved in this disorder, are the lower chambers. Their function is to contract to pump blood out of the heart and into the arteries.
The atria and ventricles contract in response to an electrical impulse. A resting heart rate for healthy people ranges between approximately 60 and 100 beats per minute.
But in some cases, these contractions can become faster and/or disorganized and put the patient at risk. This is called arrhythmia or a heart rhythm disorder.
When they originate in the atria they are called atrial heart rhythm disorders, whereas those arising in the ventricles are called ventricular heart rhythm disorders.
Ventricular fibrillation is the most severe form of cardiac arrhythmia. It involves very rapid and chaotic electrical impulses, which are ineffective in maintaining the heart’s pumping function. The ventricles no longer contract, leading to cardiac arrest. The only way to save the patient is through immediate intervention with first aid.
Causes
Ventricular fibrillation can be caused by various factors, most of which are linked to pre-existing heart conditions. The most common cause is myocardial infarction, but more broadly, any form of heart failure or heart disease can lead to cardiac arrest. In some rare cases, no underlying heart condition is found.
Symptoms and diagnosis
Unlike other arrhythmias, ventricular fibrillation is characterized by serious and immediate symptoms: loss of consciousness and sudden cardiac arrest.
One in ten deaths
Ventricular fibrillation is responsible for 10-12% of deaths worldwide, and 70% of cases of unexpected cardiac arrest.
Treatment
Ventricular fibrillation therefore requires immediate emergency treatment. Treatment consists of cardiopulmonary resuscitation (CPR) combined with immediate defibrillation.
In France, the witness must call the emergency services immediately by dialing 15.
While waiting for their arrival, they should begin chest compressions and locate an automated external defibrillator (AED): there are websites and applications that can help you locate one in seconds. If an AED is not available, the bystander must perform chest compressions until the emergency services arrive.
The bystander response time is crucial: in 90% of cases, delays in assistance lead to death.
How to perform CPR
Many organizations, such as the Red Cross (Croix-Rouge) and the Civil Defense (Protection Civile) provide CPR training. This is of course the best way to prepare for the possibility of intervening during an emergency situation.
If you witness a cardiac arrest, be prepared to intervene!
- Lay the person on a hard surface and kneel down right next to them by their side.
- Place your hands one on top of the other in the center of the chest, with your arms extended.
- Press down vertically with all your weight to apply strong compressions. Your hands should sink 5 to 6 centimeters and then rise to allow blood circulation. The compressions should ideally be performed at a rate of 100 per minute.
- After every 30 compressions, perform mouth-to-mouth if you have been trained to do so. Otherwise, continue the compressions until the emergency services arrive or until the defibrillator instructs you to stop.
What is an automated external defibrillator?
An automated external defibrillator is a device that emerged in the 1990s and which the French Ministry of Health made available to the general public in 2007. The device delivers an electric shock to restore the heart’s rhythm. In France, there are over 400,000 AEDs, not including those in hospitals.
There are two types:
- The semi-automatic, which delivers the shock when the user presses a button.
- And the automatic, which does not require this intervention.
In both cases, AEDs are equipped with voice guidance to help the user perform chest compressions and place the electrodes. The device also performs a diagnosis to decide whether or not to deliver an electric shock.
There are apps available to help locate the closest defibrillators, the most comprehensive being Stayin’ Alive.
In the long term, if the ventricular fibrillation is caused by a reversible condition, it should be treated. If not, an implantable cardioverter-defibrillator is used to continuously monitor the heart rate and deliver an electric shock to restore a normal rhythm when arrhythmia occurs. Medication can also be prescribed.
What is an implantable cardioverter-defibrillator?
The implantable cardioverter-defibrillators referred to in this article are small devices connected to leads that are secured to the heart with screws. They should not be confused with automated external defibrillators, which are available in public places.
40,000
The number of sudden cardiac deaths each year in France.
Reviewed and approved by Marine Arnaud, MD, Cardiologist at Bordeaux University Hospital (CHU)
