title: Effect of dipping status on QRS morphology in patients with hypertension.
abstract: BACKGROUND
  Prolongation of the QRS complex on the surface electrocardiogram (ECG) has been shown to be predictive of cardiovascular outcomes in selected populations. A 'nondipper' blood pressure (BP) profile is currently regarded as a risk factor in its own right for cardiovascular events and target organ damage. The predictive value of ECG parameters in hypertensives with nondipper profile has not been established.
  
  
  METHODS
  A total of 750 consecutive patients with hypertension who had been evaluated with ambulatory BP monitoring were screened for this study. One hundred and thirty-six patients who had fulfilled the inclusion and exclusion criteria were included in the final analysis. Dipper and nondipper patterns were detected and the maximum QRS duration (QRSd) measured on a 12-lead ECG was recorded.
  
  
  RESULTS
  There were 70 nondipper and 66 dipper hypertensives. There was no significant difference between the two groups regarding the daytime systolic and diastolic mean BPs, number of medications taken, and the proportion of each class of antihypertensive medications. Other variables were similar between the two groups. QRSd was significantly higher in nondippers than dippers (P=0.006). Correlation analysis revealed that the systolic BP fall at night was inversely and significantly related with QRSd (r=-0.482, P<0.001). Regression analysis further showed that the systolic BP fall at night and age were independent correlates of QRSd.
  
  
  CONCLUSIONS
  QRSd on the standard-surface 12-lead ECG was increased in patients with nondipper pattern and furthermore the systolic BP fall at night was independent correlate of QRSd in patients with hypertension.
authors.affiliation: Department of Cardiology, Duzce University, Düzce Medical School, Konuralp, Duzce, Turkey. iserdemus@yahoo.com
authors.forename: Ismail
authors.initials: I
authors.lastname: Erden
authors.forename: Emine Cakcak
authors.initials: EC
authors.lastname: Erden
authors.forename: Hakan
authors.initials: H
authors.lastname: Ozhan
authors.forename: Subhan
authors.initials: S
authors.lastname: Yalçin
authors.forename: Cengiz
authors.initials: C
authors.lastname: Basar
authors.forename: Mesut
authors.initials: M
authors.lastname: Aydin
mesh_terms: D000328:Adult; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm / Q000502:physiology; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D013599:Systole