Heart rate variability is severely impaired among type 2 diabetic patients with hypertension.
BACKGROUND
The aim of our study was to evaluate the relative effect of diabetes and hypertension on heart rate variability.


METHODS
Four age-matched groups including type 2 diabetic patients with and without hypertension, non-diabetic patients with essential hypertension and healthy control subjects were studied. Autonomic function was evaluated by the standard cardiovascular reflex tests and 24-hour heart rate variability measurement. Heart rate variability was characterized by the triangular index value and by the spectral components of the frequency domain analysis.


RESULTS
According to the two-way analysis of variance on ranks, all parameters were influenced negatively by diabetes (heart rate variability triangular index: p < 0.001; low-frequency component: p < 0.0001; high-frequency component: p < 0.001; and total power: p < 0.0001), whereas hypertension had a negative effect only on the low-frequency component (p < 0.05). The interaction between hypertension and diabetes was not significant, indicating that their effects on the heart rate variability parameters are additive. Beat-to-beat variation upon deep breathing, the most sensitive cardiovascular reflex test was also negatively influenced by both diabetes (p < 0.001) and hypertension, (p < 0.05), and their effects were additive.


CONCLUSIONS
Diabetes appears to have a greater effect on autonomic dysfunction compared with hypertension. Patients suffering from both diabetes and hypertension are at the highest risk of reduced heart rate variability. Early assessment of the autonomic nerve function is suggested in diabetic patients with hypertension.
Ildikó
I
Istenes
Anna Erzsébet
AE
Körei
Zsuzsanna
Z
Putz
Nóra
N
Németh
Timea
T
Martos
Katalin
K
Keresztes
Miklós Soma
MS
Kempler
Vági Orsolya
VO
Erzsébet
Péter
P
Vargha
Péter
P
Kempler
D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000453:epidemiology; D017776:Autonomic Pathways / Q000503:physiopathology; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000150:complications* / Q000503:physiopathology; D058065:Diabetic Cardiomyopathies / Q000150:complications* / Q000453:epidemiology; D003929:Diabetic Neuropathies / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D015203:Reproducibility of Results; D012306:Risk; D018754:Ventricular Dysfunction / Q000150:complications* / Q000453:epidemiology