title: [Association between ambulatory blood pressure levels and blood pressure variability with myocardial performance index in untreated hypertensive patients].
abstract: OBJECTIVE
  To observe the association between ambulatory blood pressure levels and blood pressure variability (BPV) with myocardial performance index (MPI) in untreated hypertensive patients.
  
  
  METHODS
  From January to September 2013, a total of 81 untreated hypertensive patients were included in this study. All patients received ambulatory blood pressure monitoring and echocardiography measurements. MPI was determined in all patients by the following formula: MPI = (isovolumic contraction time + isovolumic relaxation time)/ejection time. The patients were divided into two groups according to left ventricular MPI: patients with MPI < 0.47 (n = 39) and patients with MPI ≤ 0.47 (n = 42). The mean levels and standard deviation (SD) of 24 h, daytime and nighttime blood pressures were compared between the two groups. SD was used to express BPV. Determinants of MPI were identified by multivariate regression analysis.
  
  
  RESULTS
  24 h and daytime systolic blood pressure, 24 h, daytime and nighttime diastolic blood pressure, as well as SD of 24 h and daytime systolic blood pressure ((130.1±8.7), (134.0±8.2), (89.1±6.3), (90.9±6.4), (83.1±9.9), (13.7±3.3) and (14.2±3.5) mmHg (1 mmHg = 0.133 kPa), respectively) were significantly higher in patients with MPI > 0.47 than those ((124.8±8.7), (126.7±8.8), (84.5±7.1), (86.2±7.4), (76.4±7.5), (11.8±2.1) and (10.4±1.9) mmHg, respectively) in patients with MPI ≤ 0.47 (all P < 0.05). Multivariate regression analysis showed that 24 h diastolic blood pressure (β = 0.239, P = 0.007) and SD of 24 h systolic blood pressure (β = 0.333, P < 0.001), left ventricular mass index and early diastolic mitral annular velocity were independently associated with MPI.
  
  
  CONCLUSIONS
  The increase of diastolic blood pressure and systolic BPV are associated with the deterioration of left ventricular function.
authors.affiliation: Department of Cardiology, Peking University Third Hospital, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing 100191, China.
authors.forename: Shaomin
authors.initials: S
authors.lastname: Chen
authors.affiliation: Email: chenbaoxia@medmail.com.cn.
authors.forename: Baoxia
authors.initials: B
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Nie
authors.forename: Xinheng
authors.initials: X
authors.lastname: Feng
authors.forename: Zhaoping
authors.initials: Z
authors.lastname: Li
authors.forename: Lijun
authors.initials: L
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
mesh_terms: D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D003971:Diastole; D004452:Echocardiography; D006352:Heart Ventricles; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008943:Mitral Valve; D016277:Ventricular Function, Left