Fig. 4

Forest plot of the effect of cardiac resynchronization therapy (CRT) on left ventricular function and New York Heart Association (NYHA) functional classification improvement in different groups. Net changes in left ventricular ejection fraction (LVEF) (A); left ventricular end-diastolic dimension (LVEDD) (B); and NYHA functional classification (C) were estimated by comparing HPSP with BVP. Squares indicate the effect size of a study, with a 95% CI; and diamonds indicate the overall effect size of all studies combined