Effect of Cardiac Resynchronization Therapy on Left Ventricular Function in Patients with Heart Failure and Left Bundle Branch Block

Background: Heart failure with Left Bundle Branch Block exacerbates ventricular dyssynchrony, significantly impairing cardiac function. Cardiac Resynchronization Therapy has emerged as a transformative intervention, improving mechanical synchronization and left ventricular function in these patients.Objective: To evaluated the impact of Cardiac Resynchronization Therapy on left ventricular function in patients with heart failure and Left Bundle Branch Block at Hayatabad Medical Complex, Peshawar.Material and Methods: A retrospective study was conducted from January 2021 to December 2021, involving 100 patients with heart failure and Left Bundle Branch Block. Patients' data were analyzed for improvements in Left Ventricle Ejection Fraction, New York Heart Association class, and QRS duration. Statistical analyses were performed, with significance set at p < 0.05.Results: The study revealed significant improvements post-cardiac resynchronization therapy. The mean LVEF improvement was 25.47% (SD ± 9.08), ranging from 10% to 40% (p < 0.05). New York Heart Association class improved by an average of 2.51 points (SD ± 1.16), with most patients achieving a 3–4-point enhancement (p < 0.05). The mean reduction in QRS duration was 54.84 ms (SD ± 25.49), ranging from 10 to 99ms (p < 0.05). Responders, defined as patients with LVEF improvement ≥25%, showed significantly greater QRS reduction (65ms vs. 35ms) and NYHA class improvement (3.1 vs. 1.9 points) compared to non-responders.Conclusion: Cardiac Resynchronization Therapy significantly improves cardiac function, electrical synchronization, and symptomatic status in heart failure patients with Left Bundle Branch Block. These findings highlight cardiac resynchronization therapy's transformative potential and the importance of precise patient selection. Future research should include multicenter trials and long-term follow-ups to optimize outcomes.Keywords: Cardiac resynchronization therapy, Heart failure, Left bundle branch block, Left ventricular function, QRS duration.