Difference between ICD and pacemaker

The so-called ICD is actually an acronym for implantable cardioverter defibrillator, which is composed of two parts: a pulse generator and electrode leads. (In recent years, transvenous placement of ICD electrodes has replaced the earlier open-chest placement of epicardial defibrillation electrodes.) The device is small enough to be buried between the pectoralis major and minor muscles, or even in a subcutaneous pouch like a pacemaker. However, they are becoming increasingly powerful, providing anti-bradycardia pacing, anti-tachycardia pacing, and low-energy electrical reversal and high-energy electrical defibrillation. It receives electrical signals from the heart through an electrode catheter and constantly monitors the status of the heart's electrical activity. When the electrical activity of the heart is normal, the ICD only plays a monitoring role and the patient does not feel anything; when malignant ventricular arrhythmia appears and persists, the ICD analyzes these abnormal electrical activities of the heart according to a set program and takes different measures.

①Termination of ventricular tachycardia: The ICD can stimulate the heart by releasing electrical impulses that are faster than those of ventricular tachycardia, thereby suppressing ventricular tachycardia at an excessive speed, terminating tachycardia, and restoring the normal heart rhythm.

②Low-energy reversal: ICDs can release small electrical shocks to terminate abnormal rhythms.

③Defibrillation: mainly used for the treatment of ventricular fibrillation, similar to low-energy reversal, except that the shock energy is higher. Can be issued in 20 seconds after 20 to 30 joules of electrical energy defibrillation, such as a discharge is ineffective, can be 20 to 40 seconds apart and then discharged once, up to three times.

④When the patient is bradycardic, the ICD has a supportive pacing function to keep the patient's heart rate at a certain level and maintain the pumping function.

And general implantable pacemakers are only used for bradycardia, all types of atrioventricular block, sick sinus node syndrome, and other diseases that cause a decrease in heart rate and the treatment of arrhythmia.

So an ICD in the general sense encompasses the function of a pacemaker, is itself an implantable device like a pacemaker, and is coded using the same NBG code system as a pacemaker.