The Clinical Significance Of Decreased Heart Rate Deceleration Capacity In Dilated Cardiomyopathy Patients

Objective : To investigate the clinical significance of changes of heart rate deceleration capacity(DC)in patients with dilated cardiomyopathy(DCM)Method:DC and heart rate acceleration capacity(AC)value were detected in 69 cases of DCM patients(DCM group)and 165 patients without organic heart disease(control group) by using 24 h dynamic electrocardiogram. The cardiac structure and function were detected by using echocardiography. Patients with DCM were divided into two groups:low risk group without cardiac death and high risk group with cardiac death. The association pattern between DC value and survival rate in DCM patients were studied by Kaplan-Meier and Cox regression analysis.Results:Compared to control group, DC values [(4.0±1.82 vs 7.2±0.53)ms, P〈0.01] were significantly decreased in DCM group while AC absolute values[(-4.5±1.91 vs-7.9±1.14)ms,P<0.01] were increased, and there were significant negative correlations between DC value and LAD(r=-0.278,P<0.05) in DCM patients. Compared to low risk patients in DCM group, DC values were decreased [(2.8±1.03 vs 4.4±1.94)ms, P〈0.05] and AC values were increased [(-3.5±1.16vs-4.9±2.09),P<0.05)] in high risk patients. The decreased DC value was one of the risk factors of CD in DCM patients. There was lower survival rate in patients with DC<4.5ms than that in the patients with DC values ≥4.5ms,(log-rank=4.837,P<0.05)Conclusion:The decreased heart rate deceleration capacity represents the impaired autonomic nervous function and it is one of the risk factors of cardiac death in DCM patients. DC <4.5ms in DCM patients predicts lower survival rate.