7/31/2019 2000_reactions of the Heart Rate and Carotid Artery Pulse Wave Components to the Nitroglycerine Uptake

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Stankus A., Alonderis A., Varoneckien J ..Reactions of the heart rate and carotidartery pulse wave components to the nitroglycerin uptake. Kaunas Univerity ofMedicine, Annual Report99, 2000, P 163-164.

INSTITUTE OF PSYCHOPHYSIOLOGY AND RAEBILITATION

NEUROPSYCHOLOGY LABORATORY

REACTIONS OF THE HEART RATE AND CAROTID ARTERY PULSE WAVE

COMPONENTS TO THE NITROGLYCERINE UPTAKEA. Stankus, A. Alonderis, J. Varoneckiene

Nitroglycerine (NTG) is a potent and reliable agent for decreasing the left and right ventricularfilling pressure in the normal heart, as well as in a subject with congestive heart failure and high

pulmonary capillary pressure. We made a premise that systemic changes of the blood vessel walland heart contraction may affect carotid artery pulse wave phase characteristics: carotid arterydilates more or less, decreases or increases the impulsation from baroreceptors. Aim of the study isto assess reaction of the heart rate, its variability and blood circulation changes during thenitroglycerine test.

Methods: In this experiment, we used the methods of the polygraphy. We are recordingchanges in pulsation of the carotid artery by the local electroimpedance registration method andheart rate. The pulse wave amplitude is measured by means of volume units (ml/l). Recorded in thecarotid artery projection, pulse wave was entered through an analogue-to-digital converter into

personal computer IBM-486 by using prepared algorithms, and in each pulse wave amplitudes ofearly systolic peak (ESP) and late systolic peak (LSP) were separated. The subject during theinvestigation time is in sitting position, relaxed. In the first stage (5 min.) of our investigationregistration of the electrocardiogram, rhytmogram and relative changes of the carotid artery pulsewave amplitude was performed. In the second stage to the investigated person is given 2.5 mgnitroglycerine sublingually, and registration of the previous parameters with the changes thatoccurred after nitroglycerine uptake during 12 minutes continues. All the registered time series werecleaned from artefacts and stored as files. This way we got 3 time series. A multivariate spectralanalysis of the analysed parameters was performed. Mean values and variabilities were calculatedfrom time series each minute of the NTG test.

Results:The contingent was a group (n= 204 subjects, male-143, female-61). The vasomotortone index (ratio LSP/ESP) was 28.3 13.97 and changed from 0 to 68 %. This result may be frominadequate NTG dose or nitrate tolerance occurrence. ESP reaction during NTG test was significant.Changes of the LSP during the test were minimal. During 12 minutes after nitroglycerine uptake,carotid artery vasomotor tone index not returned to the initial level. With decrease of the vasomotortone, at the same time heart rate increased (11.3 6.14 %). Dependence of the vasomotor tone andheart rate reaction may be expressed by regression ratio %RR= 3.718 1.7*(LSP/ESP). Maximalheart rate increase was 30 %. Also it was found, that heart rate reaction to the nitroglycerine is not

always adequate to the vasomotor tone reaction. Investigated subjects were divided into 3 groupsaccording to initial heart rate increase, compared to initial heart rate level. In the I group are patientswith difference of the relative heart rate and vasomotor tone reaction less, than 11% (n= 66), in the IIgroup this difference was 11-25% (n= 88) and in III group >25% (n= 55). In the I and II groupsreaction to the nitroglycerine uptake was adequate to the changes of the vasomotor tone. In the IIgroup heart rate reaction was significantly decreased. Magnitude of this reaction not depended onthe initial heart rate level. In the I group ESP was highest (1.20-0.4 ml/l) and in the III group it waslowest (0.92-0.28 ml/l, p0.001). Theseresults confirm, that changes in the arterial wall are closely related with the changes of thehomodynamic and heart rate.

Conclusion: Heart rate and vasomotor tone index are related parameters, and they are

partially reflecting status of the systemic homodynamic. Decreased heart rate reaction to thenitroglycerine uptake shows inadequate response of the systemic homodynamic to the vascular wallchanges.