Influence of QRS prolongation on the natural history of CHF

Aims To evaluate the influence of QRS prolongation on the natural history of chronic heart failure (CHF). Methods The results of several studies carried out from 1951 to 2003 were analysed. Results (a) Isolated left bundle branch block (LBBB) is associated with an increased risk of developing cardiovascular disease and increased cardiac mortality; (b) investigations on the effect of right bundle branch block (RBBB) on mortality have yelded conflicting results; (c) the effects of the association of LBBB with left axis deviation (LAD) on further LV function deterioration remain controversial; (d) LBBB in CHF is associated with a significantly higher all-cause and sudden cardiac death mortality. Conclusions LBBB is unequivocably associated with greater disease severity and mortality in patients with CHF.