ventricular defibrillation electric shock: treatment of cardiac arrhythmias

2021-05-31 04:06 PM

The defibrillation current is delivered to the heart as a biphasic wave. This form of conduction essentially reduces the energy required for defibrillation and reduces the risk of burns and myocardial damage.

A large alternating current can stop ventricular fibrillation by bringing all the ventricular muscles to the refractory phase. This feat is achieved by the passage of a large amount of alternating current through both sides of the heart. This current passes through most of the myocardium at the same time, resulting in stimulation of all myocardium at the same time and returning them to the refractory phase at the same time. And after 3-5s stop beating. The heart begins to beat again and normally in the sinus node or another phase becomes the trigger point. However, if the re-acceptance point that is the source of the ventricular fibrillation persists, the fibrillation may recur immediately.

As current passes through both sides of the heart, the fibrillation usually ends when a current of 1000 volts is applied for a few milliseconds. Because it has to pass through the chest wall, as shown in the picture, the machine is charged with a large amount of electricity up to several thousand volts and then becomes a capacitor to discharge electricity in milliseconds through the chest wall and to the heart.

Figure. Electric shock treatment of ventricular fibrillation.

 

In most cases, the defibrillation current is delivered to the heart as a biphasic wave. This form of conduction essentially reduces the energy required for defibrillation and reduces the risk of burns and myocardial damage.

In patients at high risk of ventricular fibrillation, a small implantable cardioverter-defibrillator (ICD) battery with a subcutaneous implantable wire can be used to connect the right ventricle. This machine is set up to detect ventricular fibrillation and stop it by delivering short pulses into the heart.

Developments in power storage and batteries have allowed the development of an ICD that generates enough electricity to defibrillate via a subcutaneous implant, outside the intercostal space near the heart, rather than inside or above the heart. And installing this machine only requires minor surgery.