Left Ventricular Dyssynchrony

Heart failure (HF) is the most common nosology encountered in clinical practice. Its incidence and prevalence increase exponentially with increasing age and it is associated with increased mortality, more frequent hospitalization and decreased quality of life. An initial approach to the treatment of HF patients with reduced left ventricular (LV) systolic function and left bundle branch block (LBBB) was implantation of cardioresynchronization device using biventricular pacing. This has resulted in long-term clinical benefits such as improved quality of life, increased functional capacity, reduced HF hospitalizations and overall mortality. However, conventional cardiac resynchronization therapy (CRT) is effective in only 70% of patients. And the remaining 30% of patients are non-responders to conventional CRT. Subsequently, His bundle pacing (HBP) has been developed to achieve the same results. According to other studies HBP has showed greater improvement in hemodynamic parameters than with conventional biventricular CRT. But, nevertheless, there are significant clinical troubles with HBP. In this regard, in 2017, the left bundle branch pacing (LBBP) was developed, which demonstrated clinical advantages compared to biventricular CRT. This method has become an alternative to HBP due to the stimulation of LBB outside the blocking site, a stable pacing threshold and a narrow QRS duration. A series of case reports and observational studies have demonstrated the efficacy and safety of LBBP in patients with CRT indications. However, it is not enough data about CRT with LBBP effectiveness in LV remodeling, reducing mortality and complications. According to our hypothesis, CRT with LBBP compared with conventional biventricular CRT will significantly improve the clinical outcomes and reverse LV remodeling in patients with chronic HF with reduced LV ejection fraction and reduce the number of non-responders to conventional CRT.