What is the difference between CRT (cardiac resynchronization therapy) and an ICD (implantable cardioverter defibrillator)?

Cardiac resynchronization therapy (CRT) is used to increase diastolic filling time to help synchronize the heart's left and right ventricular contractions, interventricular and intraventricular resynchronization contractions to reduce mitral regurgitation, and to increase per-beat output by means of biventricular pacing, and is mainly used to treat heart failure.

Implantable cardioverter defibrillators (ICDs) are mainly used to recognize and promptly terminate malignant ventricular arrhythmias (defibrillation), and are mainly used to prevent sudden cardiac death. There are both differences and connections between the two.

ICD combines the functions of defibrillation and traditional pacing, and different treatments are issued for a variety of arrhythmias; while CRT-D (implantable resynchronization therapy cardioverter-defibrillator) is a combination of CRT-P (triple-chamber pacemaker) and ICD, which adds the left ventricle on the basis of traditional defibrillation to realize the synchronous function of atrial and ventricular motions of the heart, and it can synchronize the dual functions of defibrillation and pacing, and can synchronize the dual functions of defibrillation and pacing, and it can be used in the treatment of patients with heart failure and for the prevention of sudden cardiac death. It is very effective for the treatment of heart failure patients and the prevention of sudden death.