Synonyms in the broadest sense
tachycardia, electrical dissociation, cardiac arrest, defibrillator
Definition ventricular fibrillation
In contrast to atrial fibrillation, in ventricular fibrillation/ventricular flutter – as the name suggests – the chambers are the site of the event. In people with ventricular fibrillation and ventricular flutter, the heart rate is abnormally increased. Note: Ventricular flutter is referred to as ventricular fibrillation from a frequency of 250 to 350 beats per minute. Ventricular fibrillation is present when the frequency exceeds 350 beats per minute.
Symptoms
The ventricular flutter quickly turns into ventricular fibrillation, which leads to cardiovascular failure with respiratory and cardiac arrest. Unconsciousness quickly occurs because the brain, as an extremely oxygen-sensitive brain, is no longer supplied with sufficient blood. The patient is no longer responsive, does not react to pain stimuli, and the pupils are dilated and rigid (i.e. he no longer reacts to light stimuli).
Cause
Ventricular flutter and fibrillation are an expression of electrical instability of the heart. This is usually caused by diseases of the heart that lead to structural changes or functional limitations. These diseases include coronary artery disease (CHD), heart failure (cardiac insufficiency), dilatation (overstretching) or aneurysms (bulging of the muscle wall) of the heart, heart attacks and heart inflammation (e.g. myocarditis).
These diseases can cause extrasystoles, which in turn can trigger micro-reentry circulation (see atrial flutter/fibrillation). In addition to the direct diseases of the heart, changes in the electrolyte balance (changes in the blood salts) can also promote the occurrence of ventricular flutter/flicker, especially hypokalemia (too little potassium) and hypomagnesemia (too little magnesium) are risk factors. Less frequent causes are electrical accidents, cardiac trauma (e.g. in traffic accidents) or strokes.
Diagnosis
The diagnosis of ventricular flutter/fibrillation is made via the ECG. The transition from ventricular tachycardia to ventricular flutter and fibrillation is smooth. Altered, broad QRS complexes are recognizable, between which no line can be seen. While in ventricular flutter the QRS complexes usually still follow each other regularly and the ECG reminds one of a saw blade, in ventricular fibrillation only chaotic QRS complexes of varying width and height are visible.
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