Lack of correlation between QTc dispersion and morning blood pressure surge in recently diagnosed essential hypertensive patients.
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.
Kim
Min Woong
MW
Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan, University School of Medicine, Seoul, Korea.
Kim
Bum Soo
BS
Shin
Hun Sub
HS
Kim
Byung Jin
BJ
Sung
Ki Chul
KC
Kang
Jin Ho
JH
Lee
Man Ho
MH
Park
Jung Ro
JR
Kim
Hwa Mock
HM
Kim
Heung Dae
HD
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