The Changes And Clinical Significance Of Heart Rate Turbulence In Patients With Nonischemic Heart Disease

Objective: To study the changes and clinical significance of heart rate turbulence in patients with nonischemic heart disease.Methods: Total 237 inpatients and outpatients were chosen from Jan 2003 to Feb 2007.Based on having organic heart disease or not,they were classified into 2 groups:nonischemic heart disease group (n=161) and control group (n=76). According to etiopathogenisis,nonischemic heart disease group were classified into 4 subgroups:dilated cardiomyopathy (DCM)group (n=43),hypertensive heart disease group (n=56),valvular disease of the heart (VDH) group (n=30) and hypertrophic cardiomyopathy (HCM)group (n=32),besides,according to NYHA heart functional grading(Ⅱ,Ⅲ,Ⅳ),they were classified into 3 subgroups. The 24-hour Holter record of each sample was processed by BMS Century Series V2.0 DEMO HRT analysis software. HRT onset (TO) and HRT slope (TS) were determined with the previously published method. TO and TS were dichotomized at predefined cut points (TO<0% and≥0%,TS>2.5 and≤2.5ms per normal to normal interval). Patients were classified into the following 3 HRT categories:category 0:both TO and TS were normal;category 1:either was abnormal and category 2:both were abnormal. Meanwhile,these parameters,24-hour mean heart rate (24hmHR),numbers of ventricular premature complexes(VPCs),SDNN,SDANN,SDNN-index,RMSSD,PNN50,LVEDD,LVESD,LAD,IVST,LVPWT,LVEFand so on,were recorded. All patients in nonischemic heart disease group were followed up and recorded the cardiac events. Results: 1.There was no difference in age and gender between each group.Compared with the control group,the value of TO was significantly higher in patients with nonischemic heart disease(0.06±2.91vs-1.50±2.80%,p<0.001),while the value of TS was significantly lower in patients with nonischemic heart disease(3.31± 3.25vs7.86±6.15ms/RRI,p<0.001).2. Compared with the control group,the value of TO was significantly higher in patients with dilated cardiomyopathy(DCM),hypertensive heart disease and valvular disease of the heart(VDH)(p<0.001),while the value of TS was significantly lower in these patients (p<0.001),but TO and TS had not significant difference between hypertrophic cardiomyopathy(HCM) group and control group (p>0.05). Besides,TO and TS had significant difference between HCM group and the other subgroups of nonischemic heart disease (p<0.001),while they had not significant difference among the other subgroups of nonischemic heart disease group (p>0.05).3. TO was significantly different between NYHA heart functional gradingⅡandⅢ,ⅡandⅣ(p<0.05).TO was not significantly different betweenⅢandⅣ(p>0.05).TS was significantly different among subgroups of nonischemic heart disease (p<0.05). Both TO and TS had significant difference between control group and NYHA heart functional gradingⅢ,Ⅳgroup (p<0.05). Between control group and NYHA heart functional gradingⅡgroup,TS had significant difference(p<0.05),while TO had no(p>0.05)。4. The positive rate of HRT in nonischemic heart disease group(68.9%)was significantly higher than that in control group(31.6%)(p<0.001).The positive rate of HRT in the subgroups of nonischemic heart disease was 83.7%(36/43),83.9%(47/56),86.7%(26/30)and 6.3%(2/32)in DCM group,hypertensive heart disease group,VDH group and HCM group respectively. Compared with the control group,it was significantly different in the positive rate of HRT(p<0.01).The positive rate of HRT in DCM group,hypertensive heart disease group and VDH group was significantly higher than that in control group,while the positive rate of HRT in HCM group was significantly lower than that in control group. In the nonischemic heart disease group ,the positive rate of HRT in HCM group was significantly lower than that in DCM group,hypertensive heart disease group and VDH group(p<0.001),but the positive rate of HRT was not significantly different among the other subgroups of nonischemic heart diseas(ep>0.05). The positive rate of HRT in the subgroups of nonischemic heart disease was 39.7%(27/68),88.2%(45/51) and 92.9%(39/42)in NYHA heart functional gradingⅡgroup,Ⅲgroup andⅣgroup respectively. The positive rate of HRT in NYHA heart functional gradingⅢgroup andⅣgroup had significant difference with control group(p<0.001),While the positive rate of HRT in NYHA heart functional gradingⅡgroup had no significant difference with control group(p>0.05). The positive rate of HRT in the NYHA heart functional gradingⅢandⅣgroup were higher than that in NYHA heart functional gradingⅡgroup,and it was significantly different in the positive rate of HRT(p<0.001),while the positive rate of HRT between NYHA heart functional gradingⅢandⅣgroup had no significant difference(p>0.05)。5. The constituent ratio of HRT in nonischemic heart disease group and the subgroups of it had significant difference with control group(p<0.05). The constituent ratio of HRT had no significant difference among DCM group,hypertensive heart disease group and VDH group(p>0.05),While HRT constituent ratio of these groups had significant difference with HCM group(p<0.001). The constituent ratio of HRT had significant difference among NYHA heart functional gradingⅡgroup,Ⅲgroup andⅣgroup(p<0.01).6. In the nonischemic heart disease group:TO and LVEF were negatively correlated(p<0.01). TO and LVEDD,LVESD,NYHA heart functional grading were positively correlated(p<0.01). There was no significant correlation between TO and SDNN,SDANN,SDNN-index,24hmHR and the numbers of VPCs(p>0.05).TS and LVEF,SDNN,SDANN were positively correlated(p<0.05).TS and LVEDD,LVESD,NYHA heart functional grading,24hmHR,the numbers of VPCs were negatively correlated(p<0.05). There was no significant correlation between TS and SDNN-index(p>0.05).7. During follow up (14.39±11.92 months),101 of 161 patients with nonischemic heart disease caught cardiac events. The value of TO was remarkably higher in patients with cardiac events than in those without cardiac events(0.83±2.91vs-1.20±2.43%,p<0.001).TS was remarkably lower in patients with cardiac events(2.13±2.05vs5.29±5.27ms/RRI,p<0.001).LVEF,SDNN and SDANN were obviously different between patients with and without cardiac events(p<0.05).The value of TO in DCM group,hypertensive heart disease group and VDH group was remarkably higher in patients with cardiac events than in those without cardiac events(p<0.05).TS was remarkably lower in patients with cardiac event(sp<0.05),while the value of TO or TS in HCM group was not obviously different between patients with and without cardiac events(p>0.05). The positive rate of HRT was respectively 85.1%(86/101)and 41.7%(25/60)in patients with and without cardiac events. The former was remarkably higher than the latter(p<0.001).The composition of HRT was obviously different between patients with and without cardiac events(p<0.001).The composition of HRT in 101 patients with cardiac events was 15 (HRT0),24(HRT1)and 62 (HRT2) respectively. The composition of HRT in 60 patients without cardiac events was 35 (HRT0),13(HRT1)and 12 (HRT2) respectively. The proportion of HRT1 and HRT2 in patients with cardiac events was obviously higher than that in patients without cardiac events. Besides,univariate and multi variable logistic regression analyses discovered that abnormal TO and TS had the most distinguished prognostic meaning to the relative risk of happening main cardiac events.Conclusions: 1,The HRT in patients with nonischemic heart disease is decreased,especially in high risk patients with nonischemic heart disease it becomes more stunted. The value of TO is higher and TS is lower in patients with nonischemic heart disease than that in control patients.2,HRT can reflect the heart functional grading and serious degree of heart failure of patients with nonischemic heart disease. The TS is more powerful to reflect left ventricular function than TO.3,Both TO and TS can reflect the cardiac autonomic nerve status of patients with nonischemic heart disease.4,The high risk of patients with nonischemic heart disease may be found out by examining HRT. HRT can well predict the prognosis of patients with nonischemic heart disease. So HRT can be a useful risk stratified marker in nonischemic heart disease.5,Univariate and multi variable logistic regression analyses discover that abnormal TO and TS have the greatest value to the prognosis of patients with nonischemic heart disease. 6,The subgroups analyses discover that the HRT is not decreased in HCM patients,so HRT can fail to predict the clinical prognosis in HCM patients.