Heart failure is a common disease that seriously endangers human health. In the past, treatment was mostly drug-based, and nearly half of the patients died within 5 years after the onset of heart failure symptoms, so some people call heart failure “the malignant tumor of the heart. Many patients with heart failure, especially when combined with left bundle branch block, have varying degrees of cardiac contraction incoordination, leading to further weakening of cardiac function. CRT (also known as triple-chamber pacemaker) breaks the traditional concept by burying the pulse generator under the skin and excites the right and left ventricles with pulses from three electrodes, which tightly couples the electrical and mechanical functions of the heart, realizing the coordination and synchronization of heart contraction and improving heart function, thus miraculously reducing the overall mortality rate of patients with severe heart failure by 36% based on rational drug therapy. It can be said that CRT for heart failure is a miracle in the field of cardiology in the last decade, and its appearance has enabled many heart failure patients to see the light of recovery. Although CRT has now become a globally recognized sword in the treatment of heart failure, the operation is complex and technically demanding, and previously there was only one hospital in the province that could independently perform this operation. Looking to the future, we will make better use of this technology to bring hope for recovery to the majority of heart failure patients. Mechanism of cardiac resynchronization therapy (CRT) for heart failure patients Cardiac resynchronization therapy (CRT) for heart failure is a miracle that has emerged in the field of cardiology in recent years. In less than fifteen years, it has magically jumped three levels, from a Class III indication (contraindication) to a Class I indication, as a new technology for the treatment of heart disease that has been continuously explored and intensively researched. Electrical and mechanical functions are the basic functions of the heart, and previously, the disorders and failures of these functions were treated separately, but CRT has broken this traditional concept by magically coupling the electrical and mechanical functions and disorders of the heart, considering them in an integrated manner, and implementing treatment. Internal medicine and cardiovascular physicians encounter heart failure patients almost every day, and CRT as an important technique for heart failure treatment, we should be familiar with its treatment mechanism in order to make this new technology benefit more heart failure patients.