Thesis topic proposal
Péter Légrády
Investigation of cardiac autonomic neuropathy in conditions with high cardiovascular risk


Institute: University of Szeged
theoretical medicine
Graduate School of Multidisciplinar Medical Scienses

Thesis supervisor: Péter Légrády
Location of studies: 1st Depatment of Internal Medicine, Faculty of Medicine, University of Szeged, H-6720 Szeged, Korányi fasor 8-10.Hungary
Abbreviation of location of studies: ÁOK

Description of the research topic:

The sympathetic nerve system has an important role in the pathogenesis not only of
hypertension (HT) and diabetes mellitus, but also of the metabolic syndrome, congestive heart
failure, and renal insufficiency. According to the newer concepts HT is a syndrome involving
discrete blood pressure (BP) thresholds, the assessment of an individual's risk for
cardiovascular events and the target organ damages. The pathogenesis of HT is of highly
sophisticated complexity, but increased sympathetic nerve activity (SNA) plays a major role.
Stress also plays a role in the activation of SNA.
The CAN may cause symptoms ranging from resting tachycardia to sudden cardiac death. The
early parasympathetic damage may lead to a relative sympathetic overactivity with the
development of an increased heart rate (HR) before HT has appeared. The baroreflex is one of
the most important mechanisms for preventing excessive changes in BP. The baroreflex
sensitivity (BRS) is an index of the sensitivity of arterial baroreflex modulation of HR.
Aims: To investigate CAN in HT patients with and without diabetes mellitus. To look for
any association between the duration of HT, BP values and CAN; between target organ
damages of HT and CAN; antihypertensive therapeutic efforts and CAN. To investigate CAN
in patients with chronic renal failure with or without diabetes mellitus. To look for any
association between estimated glomerular filtration rate and CAN; between complication of
chronic renal failure (anemia – plasma erythropoietin, osteodystrophia – plasma Ca, P,
parathormone) and CAN.
Methods: An oral glucose tolerance test will be performed in all non-diabetic individuals in
order to exclude diabetes mellitus and impaired glucose tolerance. The CAN will be assessed
by means of the five standard cardiovascular reflex tests proposed by Ewing. The
parasympathetic function was characterized via the changes in HR in response to deep
breathing, to the Valsalva manoeuvre, and to standing up (30/15 ratio). The sympathetic
function was characterized via the systolic BP changes in response to standing up and via the
diastolic BP changes in response to a sustained handgrip. In all tests, normal values will be
scored 0, borderline values 1, and abnormal values 2. The sum of the scores gives the total
CAN score. A patient will be considered as CAN-positive if the score is 2 or higher (at least 2
tests with borderline or 1 test with abnormal values). Spontaneous BRS will be calculated in
10 minutes lying and 10 minutes standing positions via a sequence (time-domain) method
using a software package for BRS analysis (Nevrokard BRS 5.1.3; Medistar). Data necessary
for calculation will generated via a beat-to-beat data acquisition system by finger
photoplethysmography (Finometer, TPD Biomedical Instruments) at 200 Hz combined with
an ECG.

Required language skills: English
Recommended language skills: English
Further requirements: 
TDK munka

Number of students who can be accepted: 1

Deadline for application: 2017-03-15

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