Correlation Study Between Serum Level of Cardiac M2-muscarinic Receptor Autoantibody and Hypertrophic Cardiomyopathy / 中国循环杂志

ABSTRACT

Objectives: To study serum level of M2-muscarinic receptor autoantibody (M2-AAb) in hypertrophic cardiomyopathy (HCM) patients with its relationship to relevant clinical parameters. Methods: Our research included in 2 groups HCM group, 133 patients and they were divided into 3 subgroupsObstructive hypertrophic cardiomyopathy (HOCM) subgroup, 72, Latent obstructive hypertrophic cardiomyopathy (LHOCM) subgroup, 22 and Non-obstructive hypertrophic cardiomyopathy (NOCM) subgroup, 39; since there was no obstruction of left ventricular outflow tract (LVOT) in LHOCM and NOCM patients at resting, LHOCM and NOCM patients were combined as LHOCM+NOCM subgroup, 61 in comparison with HOCM subgroup. And Control group, 40 subjects had no organic heart disease and autoimmune diseases which were confirmed by 12 lead ECG, transthoracic echocardiography and routine hematological tests, they were not using β-blockers, glucocorticoids and immune-suppressants. Serum levels of M2-AAb were examined by ELISA, the relationship between M2-AAb and relevant clinical parameters were studied. Results: Compared with Control group, HCM group had increased serum level of M2-AAb [22.91 (17.21, 29.64) ng/ml] vs (17.14±5.66) ng/ml, P<0.01; M2-AAb was similar among HOCM, LHOCM and NOCM subgroups; M2-AAb in female patients were higher than male, P=0.001. Further investigation presented that the patients with family history of sudden death had the higher M2-AAb, P<0.05; patients with atrial fibrillation (AF) or left atrial diameter (LAD)≥50 mm or moderate to severe mitral regurgitation (MR) had the higher M2-AAb than those without such problems, all P<0.05. In HCM group, log M2-AAb was positively related to resting LVOT gradient (r=0.178, P=0.040); in HOCM subgroup, log M2-AAb was marginal positively related to resting LVOT gradient (r=0.224, P=0.058). Conclusions: Serum M2-AAb was elevated in HCM patients; gender, family history of sudden death may affect M2-AAb level; patients combining AF or LAD≥50 mm or moderate-severe MR had the higher M2-AAb and it was related to resting LVOT gradient.