Value of extreme left axis deviation in patients with complete left bundle branch block.

INTRODUCTION

Complete left bundle branch block (LBBB) is associated with increased risk of cardiovascular events. The value of extreme deviation of the QRS axis to the left (LAD) in the context of LBBB is controversial.

OBJECTIVE

To evaluate whether LAD (-45°) in patients with LBBB is a marker of systolic dysfunction and ventricular remodeling.

MATERIAL AND

METHODS

Cross-sectional cohort study including 102 patients with LBBB who underwent echocardiography to assess left ventricular (LV) diameters, wall thickness and ejection fraction (EF).

RESULTS

Mean age was 67.9 ± 13 years. 48 % were women. 80.4 % met Strauss criteria for LBBB and 28.4 % had LAD. The LAD group showed lower EF (32.2 ± 12 % vs. 46.7 ± 17 %, p = 0.00009) and higher LV end-diastolic diameter index (34.8 ± 9 vs. 30.9 ± 6, p = 0.011). LAD had 45 % sensitivity, 88 % specificity, positive predictive value of 0.79 and negative predictive value of 0.62 for identifying reduced EF. Cardiomyopathy diagnosis was more frequent in the LAD group (93.1 % vs. 61.6 %; p = 0.0016). LV hypertrophy prevalence was similar between groups, but LAD patients had higher prevalence of eccentric LV hypertrophy.

CONCLUSION

In LBBB, LAD (-45°) identifies patients with worse systolic function, greater degree of LV dilatation, and more eccentric hypertrophy. Additionally, cardiomyopathy prevalence was higher in this population.