Defibrillation in the Treatment of Cardiac Arrhythmias | Wellbeing

What is Defibrillation?

Defibrillation is a medical procedure that uses electric current to re-establish a normal heart rhythm. This method is often applied to cases of heart rhythm disorders such as atrial fibrillation or tachycardia. The shock causes depolarization of all stimulated heart muscle cells. This method helps the sinus node re-establish its role in controlling the heart rhythm.

Defibrillation is not a method of stimulating the heart to beat using electric current (pacing). This method helps resynchronize electrical activity in heart muscle cells, helping the heart function rhythmically again. For cases of cardiac arrest due to ventricular fibrillation or ventricular tachycardia where the patient loses consciousness and hemodynamic stability, immediate external defibrillation is required.

Defibrillation Procedure

Defibrillation needs to be performed quickly; anesthesia is not required for the patient. The effectiveness of defibrillation depends on the shock voltage (energy) and tissue impedance (such as patient body habitus, chest, lung condition). All tachyarrhythmias causing circulatory arrest, loss of consciousness, or severe hemodynamic compromise are indicated for emergency external defibrillation. The steps for performing defibrillation are as follows:

1. Preparation: In case of emergency defibrillation, proceed immediately. For elective (planned) cardioversion, the procedure is clearly explained to the patient, who agrees and signs a consent form. The defibrillator must be in good condition. The two shock paddles must be clean, have good contact with the patient's skin, and discharge at the correct set power. Prepare equipment for monitoring electrocardiogram (ECG), blood pressure, intubation tools, etc.

2. Attaching Electrodes (Paddle Placement): Quickly apply conductive gel to the two electrode paddles. Place the two paddles on the patient's chest. One paddle is placed on the right border of the sternum, 1 cm from the sternum and 3 cm from the clavicle. The other paddle is placed at the apex of the heart. Set the energy level of the defibrillator for the first shock at 200J. The operator observes the patient and the surroundings; when it is safe, proceed to discharge the electricity.

3. Shock Delivery: A high-energy current enters the chest, passing through the heart in a very short time, helping to restore normal heart rhythm. The resuscitation team continues to maintain the patient's respiration. Sinus rhythm will be re-established. If the ECG still shows coarse ventricular fibrillation or ventricular tachycardia, proceed with a shock at an energy level of 300J. If there is still no result, increase the energy level to 360J until sinus rhythm is re-established.

4. Post-Defibrillation Monitoring: The patient will be monitored to ensure no complications occur. Clinically monitor heart rate, respiratory rate, blood pressure, and arterial blood oxygen saturation continuously on the screen. If arrhythmias appear, they must be treated with anti-arrhythmic drugs. Adjust electrolytes. Monitor the patient for the first 24 hours, investigate and treat the underlying causes of the patient's arrhythmia.

Defibrillation is an effective method in treating arrhythmias, helping patients quickly return to normal life. This is a method proven to be safe and has a high success rate. However, this method requires clear indications and is usually performed by emergency resuscitation doctors. Except for emergency defibrillation cases which need to be done immediately, for some other heart rhythm disorders, you can also consult a doctor for advice and implementation of this method.

Article uses reference materials from the document: Guidelines on Internal Medicine Technical Procedures, Cardiology specialty of the Ministry of Health (2014), Medical Publishing House, Hanoi.