A Randomized Controlled Trial of LOT-CRT Versus conventionaL BiVP in Heart Failure Patients With NICD

Cardiac resynchronization therapy is a standardized treatment strategy for patients with chronic heart failure complicated by wide QRS waves. With the continuous development of physiological pacing technology, traditional cardiac resynchronization therapy, namely biventricular pacing technology, is constantly challenged. Left bundle branch area pacing (LBBAP), as the main method of physiological pacing technology, is currently increasingly widely used in clinical practice. In recent years, research has mainly focused on heart failure patients with wide QRS waves such as non ischemic cardiomyopathy and typical left bundle branch block (LBBB). The recently published LBBP-RESYNC study was a randomized controlled study comparing left bundle branch pacing (LBBP) and biventricular pacing. The results showed that LBBP can achieve better improvement in left ventricular function compared to traditional biventricular pacing.

Compared with patients with typical LBBB, traditional biventricular pacing synchronized treatment is less effective in chronic heart failure patients accompanied by intraventricular block (NICD), which is closely related to the electrophysiological mechanism of LBBB. The blocking site of typical LBBB is generally located within the His bundle to the proximal end of the left bundle branch, while the distal end of the left bundle branch is relatively healthy. Therefore, LBBP can completely correct this type of LBBB and significantly narrow the QRS wave; The electrophysiological mechanism of NICD is relatively complex, and there may be multiple blocking sites, and LBBP cannot be completely corrected. How to improve the treatment efficacy and clinical prognosis of chronic heart failure patients with NICD is an important scientific issue that urgently needs to be solved. It is unclear whether left bundle branch pacing technology can provide support for cardiac function in such patients.

Traditional biventricular pacing combines right ventricular and left epicardial pacing; LBBAP combined with left ventricular epicardial pacing, also known as LOT-CRT, is an innovative pacing method. This study aims to explore the application value of LBBAP in patients with chronic heart failure and NICD.

Inclusion criteria

• Ischemic or non ischemic cardiomyopathy
• Optimal medical therapy for at lest 3 months
• NYHA class II-IV
• LVEF≤35% as assessed by echocardiography
• Sinus rhythm (may have paroxysmal atrial fibrillation)
• QRS duration ≥ 150ms
• Intraventricular block (NICD), QRS morphology is neither LBBB nor RBBB

Exclusion criteria

• Valvular heart disease that requires or has undergone surgical intervention
• After mechanical tricuspid valve replacement
• Persistent or permanent atrial fibrillation or atrial flutter
• Second or third degree atrioventricular block
• Have a history of acute myocardial infarction within 3 months prior to enrollment
• Patient's expected survival time is less than 12 months
• Pregnant or planned to conceive
• Ventricular septal hypertrophy (ventricular septal thickness exceeds 15mm at the end of diastole)
• Patients with simple and persistent left superior vena cava
• Patients with existing pacemaker implantation