Objective To observe the anti-cardiac myosin heavy chain IgG changes and efficacy of the antibody titration during the treatment of dilated cardiomyopathy (DCM ) complicating heart failure by a large number of gamma globulin .Methods 28 inpa-tients with dilated cardiomyopathy complicating heart failure were taken as the experimental group ,28 cases of healthy examination as the control group .The anti-cardiac myosin heavy chain IgG antibodies were detected by ELISA ;moreover ,among the patients with heart failure treated by the conventional therapy ,14 cases were selected and added large dose of gamma globulin for observing the curative effect .The remaining 14 cases were taken as the standard control group of this experiment .The anti-cardiac myosin heavy chain IgG antibodies were detected by ELISA .Results The anti-cardiac myosin heavy chain IgG antibodies before gamma globulin therapy in the DCM complicating heart failure group had statistical difference compared with the healthy examination goup (P<0 .05);in the 14 cases of heart failure treated by large dose of gamma globulin ,11 cases (78 .57% ) in the treatment group were improved ,while 5 cases(35 .71% ) in the standard control group were improved ,the anti-cardiac myosin heavy chain IgG antibody had no significant differences between the gamma globulin treatment group and the healthy examination group .The left ventricular ejection fraction(LVEF) in the gamma globulin treatment group was increased from (36 .12 ± 9 .98)% to (46 .15 ± 12 .18)% ,the left ventricular end-diastolic diameter was decreased from (59 .68 ± 9 .60) mm to (50 .05 ± 10 .20) mm ,the effects after gamma glob-ulin treatment were more significant than the conventional traditional control group .Conclusion Large dose of gamma globulin for treating dilated cardiomyopathy complicating heart failure has more significant effect than the traditional method ,reduces the titra-tion of in vivo anti-cardiac myosin heavy chain IgG antibody and contributes to explain the drug action mechanism from immune mechanism .