Clinical Determinants of Left Ventricular Ejection Fraction Deterioration in Patients Suffered From Complete Left Bundle Branch Block

Background: Recently, the deleterious effects of left bundle branch block (LBBB) on left ventricular systolic function have been taken into consideration. Objectives: The present study aimed to identify underlying factors that predict left ventricular ejection fraction (LVEF) deterioration in patients suffered from complete LBBB. Patients and Methods: In a retrospective case-control study, the data of 220 consecutive patients diagnosed with LBBB on their electrocardiograms were assessed. They were referred to Isfahan Heart Center in Isfahan Province, Iran in 2013. LVEF deterioration was defined as a decrease in LVEF at least 10% between the baseline and follow-up echocardiography study. Thus, achieving the LVEF values ≤ 40% in patients with an initial EF of > 50% was considered LVEF deterioration. Results: Among 220 patients, 40% of LBBB patients suffered LVEF deterioration within 3 months of initial assessment. The group with LVEF deterioration had higher male to female ratio, had higher NYHA score, and suffered more from systolic hypertension than another group. Those with coronary artery disease (CAD) had also significantly lower LVEF than non-CAD ones. Adverse associations were revealed between systolic blood pressure and LVEF measurement (r = -0.193, P = 0.006) as well as between NYHA score and LVEF (r = -0.215, P = 0.002). A multivariable logistic regression model showed that among baseline variables, male gender (OR = 3.218, P < 0.001), history of systolic hypertension (OR = 2.012, P = 0.029), higher NYHA score (OR = 1.623, P = 0.005), and the presence of coronary artery disease (OR = 2.475, P = 0.028) could effectively predict LVEF deterioration in patients with LBBB. Conclusions: Male gender, history of hypertension, high NYHA score, and the presence of CAD predict LVEF deterioration in patients with LBBB.