QT dispersion in type 2 diabetic patients with altered diurnal blood pressure rhythm.
BACKGROUND
QT dispersion (QTd) is a good prognostic marker in type 2 diabetic patients without previous cardiovascular disease. Diabetic patients with an attenuated decline in nocturnal blood pressure (non-dippers) have been shown to have increased risk of diabetic complications, vascular events and mortality.


OBJECTIVE
The aim of this study was to evaluate the relationship between diurnal blood pressure rhythm, QTd and microvascular complications in type 2 diabetic patients.


METHODS
Cardiovascular autonomic function tests, 24-h ambulatory blood pressure monitoring and urinary albumin excretion measurements were performed in healthy controls (n = 25), normoalbuminuric (n = 34) and microalbuminuric (n = 23) type 2 diabetic patients. QTd was assessed manually from 12-lead surface electrocardiograms.


RESULTS
Compared with the controls, both normoalbuminuric and microalbuminuric diabetic patients had increased QTd (59.11 +/- 15.86; 60.27 +/- 17.95 vs. 40.48 +/- 10.92, p < 0.001 and p < 0.001, respectively). Similarly, diabetic patients had increased QTd regardless of the presence of autonomic neuropathy. On the other hand, non-dipper diabetic patients had increased QTd compared with the controls and dipper diabetic patients (69.73 +/- 14.50 vs. 40.48 +/- 10.92; 47.84 +/- 9.62 ms, p < 0.001). There was a negative correlation between QTd and diurnal diastolic blood pressure change (r = -0.48, p < 0.0005).


CONCLUSIONS
Patients with type 2 diabetes mellitus were found to have increased QT dispersion irrespective of the presence of diabetic autonomic neuropathy. However, QT dispersion in dipper diabetic patients was similar to the controls. This finding might point out that attenuated decline of nocturnal blood pressure could be a more sensitive marker for autonomic neuropathy.
Deyneli
O
O
Marmara University Division of Endocrinology and Metabolism, Istanbul, Turkey. odeyneli@marmara.edu.tr
Ersöz
H O
HO
Yavuz
D
D
Fak
A S
AS
Akalin
S
S
D000419:Albuminuria / Q000503:physiopathology; D001342:Autonomic Nervous System Diseases / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis