title: Lack of correlation between QTc dispersion and morning blood pressure surge in recently diagnosed essential hypertensive patients.
abstract: BACKGROUND
  Cardiovascular events are known to occur more frequently in patients with a high morning surge in blood pressure (BP), but the correlation between a morning BP surge and corrected QT dispersion (QTc) has not been confirmed to date.
  
  
  RESULTS
  The correlation between the morning BP surge and QTc was studied in 82 patients recently diagnosed with high BP (47 males, 35 females). Twenty-four-hours BP monitoring was conducted to classify patients into dipper (n=45) or nondipper (n=37) groups according to the degree of nocturnal BP reduction. QTc was found to be significantly longer in the nondippers compared with the dippers (36.1+/-17.2 vs 47.6+/-20.7, p<0.001). In addition, there was a significant increase in the end-diastolic interventricular septum thickness (IVSd), left ventricular posterior wall thickness in diastole (PWT) and left ventricular mass index (LVMI) in the nondippers vs the dippers (respectively, 0.93+/-0.09 vs 1.03+/-0.05, p<0.001, 0.94+/-0.09 vs 1.01+/-0.04, p<0.01, 109.7+/-12.8 vs 129.1+/-20.9, p<0.001). QTc had a significant positive correlation with nighttime BP, IVSd, PWT, and LVMI, but negatively correlated with the nocturnal BP reduction rate. These results were maintained even after adjusting for age and gender. However, a significant correlation between the morning BP surge and QTc was not confirmed.
  
  
  CONCLUSIONS
  In the present nondipper hypertensive patients, QTc, nighttime BP, LVMI, and wall thickness were significantly greater than in the dipper patients. However, there was no significant correlation between the morning BP surge and QTc.
authors.affiliation: Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan, University School of Medicine, Seoul, Korea.
authors.forename: Min Woong
authors.initials: MW
authors.lastname: Kim
authors.forename: Bum Soo
authors.initials: BS
authors.lastname: Kim
authors.forename: Hun Sub
authors.initials: HS
authors.lastname: Shin
authors.forename: Byung Jin
authors.initials: BJ
authors.lastname: Kim
authors.forename: Ki Chul
authors.initials: KC
authors.lastname: Sung
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Kang
authors.forename: Man Ho
authors.initials: MH
authors.lastname: Lee
authors.forename: Jung Ro
authors.initials: JR
authors.lastname: Park
authors.forename: Hwa Mock
authors.initials: HM
authors.lastname: Kim
authors.forename: Heung Dae
authors.initials: HD
authors.lastname: Kim
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular; D008297:Male; D008875:Middle Aged