ventricular fibrillation

Ventricular fibrillation: description

Ventricular fibrillation is a rhythm disorder originating in the heart chambers. It is always life threatening and can lead to death within minutes.

Normally, the muscle cells of the ventricles contract 60 to 80 times per minute. The blood collected in the heart chambers is pumped into the systemic circulation through a coordinated contraction of the heart muscle, the heartbeat. Between heartbeats, the heart chambers fill with blood again.

The signal for a heartbeat arises in the so-called sinus node, which is located in the atria. This electrical signal is routed in order and goes out when all muscle cells are contracted. With ventricular fibrillation, this order is suddenly disturbed. There are so-called circular excitations in the chamber. Frequencies of up to 800 per minute can occur.

Due to this very fast frequency, however, no more effective heartbeats occur in ventricular fibrillation. Because the much too large number of disordered excitations, the muscle cells can no longer synchronously contract. There is therefore no more blood pumped into the systemic circulation. A pulse is no longer felt by those affected. It comes to cardiac arrest.

Ventricular fibrillation: symptoms

The symptoms of ventricular fibrillation are similar to cardiac arrest. Those affected are unconscious, pale, their lips blue, their pupils wide and rigid. Breathing stops. A pulse is not palpable. Sometimes, those affected have drowned or eingekotet.

Ventricular fibrillation: causes and risk factors

In most cases, ventricular fibrillation is caused by a serious heart condition such as a heart attack. Ventricular fibrillation can also have many other causes:

• coronary heart disease (CHD)
• Deformation on the walls of the heart (cardiac wall aneurysm following myocardial infarction)
• pronounced heart failure
• Myocarditis (myocarditis)
• congenital heart defects
• pulmonary embolism
• current accident
• Medicines, drugs, poisoning
• Lack of oxygen (suffocation, drowning)
• Disorders of the mineral balance (eg potassium deficiency)
• Fluid accumulation in pericardium (pericardial effusion)
• congenital malformation in the conduction system of the heart

Ventricular fibrillation: diagnosis and examination

Ventricular fibrillation is always a life-threatening event. There is no time for an extended physical examination. If the person is unconscious and can no longer feel his pulse, the patient must first be resuscitated without diagnosis and the emergency physician must be called.

If a defibrillator is present, the existing electrodes are glued or held on the chest. The defibrillator analyzes the heart rhythm. In a so-called electrocardiogram (ECG), ventricular fibrillation becomes visible through a “flicker wave”. The layperson can use software to give instructions to a publicly available defibrillator (AED) on what to do.

Ventricular fibrillation: treatment

When ventricular fibrillation is trying to bring the heart rhythm by a surge back into the right rhythm. At the same time, current is directed into the body of the person concerned via the electrodes at the push of a button. Because all muscles get an electrical impulse at the same time, their following activity can be synchronized again. In a successful resuscitation, the heart begins to beat again. The earlier a defibrillation is performed, the better the chances of survival of those affected. Sometimes the process has to be repeated.

If people are at high risk for ventricular fibrillation due to heart disease, they may use a so-called implantable defibrillator as a precautionary measure. He is about the size of a pacemaker and continuously measures the heart currents. If the ventricular fibrillation occurs, he delivers a surge. So he does not protect himself from the arrhythmia itself, but reacts to it.

Ventricular fibrillation: disease course and prognosis

The prognosis of ventricular fibrillation depends on many factors. Of particular importance, however, is the time of defibrillation. If it is performed immediately, for example, because the person is already in the hospital or an AED is within reach, it leads in more than 95 percent of cases to success. The survivor’s chance of death decreases by about ten percent per minute of sustained ventricular fibrillation if no defibrillation occurs.

If defibrillation has been successful, it is still possible that the brain and other organs have been damaged. Especially if the resuscitation measures were carried out very late, the risk of permanent brain damage is considerable.

There is a high risk that the arrhythmia will recur after an episode of ventricular fibrillation. An implantable defibrillator can reduce the risk of dying as it instantly defibrillates when ventricular fibrillation occurs. The implanted defibrillator should be checked regularly by a physician.

Ventricular fibrillation is always deadly if left untreated. One should therefore have no fear to revive those affected or defibrillate. Possible injuries that may occur are compared to the prognosis of ventricular fibrillation irrelevant.