Cardiac arrest affects between 40 and 50 thousand people in Europe each year, causing the death of 90% of them, and ventricular fibrillation is most often the cause. What exactly is ventricular fibrillation? What is it due to? How to take care of it? The answers from Professor Gérard Helft, cardiologist and president of the French Federation of Cardiology (FFC).
Arrhythmia, rhythm disturbances: What is ventricular fibrillation?
Ventricular fibrillation is an arrhythmia characterized by chaotic and rapid contraction of the cardiac ventricles, the lower chambers of the heart. “It is the most serious arrhythmia there is, because in the absence of very rapid treatment, it leads to the death of the person within a few minutes.” indicates Professor Helft. In fact, when it occurs, the ventricles of the heart are no longer able to contract: the pulsations are very rapid and asynchronous, so that the heart is no longer able to effectively pump the blood – which carries the This results in a reduction in blood flow and oxygenation of the rest of the body and in particular the brain.
It takes little more than 5 minutes for the victim to develop irreversible brain damage, due to oxygen deprivation. Ventricular fibrillation is the most common cause of sudden death. It is responsible for 10 to 12% of deaths worldwide, and 70% of cases of unexpected cardiac arrest, without previously diagnosed cardiac pathology.
What are the causes of ventricular fibrillation?
In more than half of cases, ventricular fibrillation is the consequence of coronary artery disease, particularly myocardial infarction. “Myocardial infarction is the result of obstruction of a coronary artery, which prevents blood supply to the heart, potentially causing ventricular fibrillation.” explains Professor Helft.
But ventricular fibrillation can also be the consequence of any cardiac pathology: dilated heart disease, hypertrophic heart disease, valvular heart disease, etc. Ventricular fibrillation can also result from structural abnormalities of the heart, electrolyte disorders, drug poisoning or cardiac trauma. .
Finally, if the tests do not identify any disorder causing the problem, we say that the ventricular fibrillation is idiopathic, i.e. of unknown cause.
What are the symptoms of ventricular fibrillation and how to recognize it?
Ventricular fibrillation leads to immediate loss of consciousness followed by cardiac arrest. “It can appear suddenly, without any warning signs.” adds the specialist.
ECG: how to make the diagnosis?
Fainting (loss of consciousness) with respiratory arrest is sufficient for the diagnosis of cardiac arrest. It is not necessary to look for the pulse which is absent. During emergency treatment, an electrocardiogram (ECG) must be performed to identify ventricular fibrillation, the cause of cardiac arrest.
Which is more serious, atrial or ventricular fibrillation?
These are two very different pathologies whose level of severity is not comparable. “Atrial fibrillation is characterized by the disordered and ineffective contraction of the heart’s atria. Although it can cause more serious complications, atrial fibrillation is treatable and is generally not fatal.” indicates the cardiologist. The most common symptoms of atrial fibrillation are palpitations, sweating, fatigue, shortness of breath, dizziness or chest discomfort.
Treatment, electric shock: how to urgently treat ventricular fibrillation?
Ventricular fibrillation is an absolute emergency that requires extremely rapid treatment to have any chance of survival. “Ventricular fibrillation leads to cardiac arrest, which should ideally be recognized by a witness. The procedure to follow is then to call for help (15), and to perform a cardiac massage while waiting for their arrival, in order to allow the heart to continue to eject blood in order to irrigate the body and in particular the brain.” summarizes Professor Helft.
Treatment is then based on cardiopulmonary resuscitation with immediate defibrillation. Once on site, the emergency services therefore perform defibrillation by electric shock, in order to restart cardiac activity. Unfortunately, in more than 90% of cases, ventricular fibrillation is not treated quickly enough, resulting in the death of the patient. Note also that patients successfully resuscitated after ventricular fibrillation are at high risk of suffering another episode.
“The high death toll could be significantly improved if the population was more widely trained to recognize the signs of cardiac arrest and to perform cardiac massage. There is a real public health issue here, which the FFC has made its main focus.” underlines the cardiologist.
After defibrillation treatment, if the ventricular fibrillation was caused by a curable disorder, it must be managed.
What is the difference with torsade de pointes type ventricular tachycardia?
Torsades de pointes ventricular tachycardia is a special type of ventricular tachycardia that occurs in people with a particular disorder of the electrical activity of the heart called long QT syndrome. This syndrome can be present from birth, or favored by predisposing factors such as: hypokalemia (low potassium level), hypomagnesemia (low magnesium level), hypothyroidism, eating disorders, very fast heart rate. slow, certain drug treatments such as anti-arrhythmics, certain antidepressants or certain antivirals.
Torsade de pointes is generally self-limiting, causing few symptoms (discomfort, syncope). But they must be treated urgently, because they can lead to ventricular fibrillation.