Date of Award

Spring 2004

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering

First Advisor

Stanley S. Reisman

Second Advisor

Sina Zaim

Third Advisor

Richard Greene

Abstract

This thesis is a study to measure the changes in heart rate variability due to the activity of the autonomic nervous system caused by the Enhanced External Counterpulsation treatment. The treatment is a non surgical, mechanical procedure that can reduce the symptoms of angina or Congestive Heart Failure, presumably by stimulating the opening, or formation of, small branches of blood vessels (collaterals) to create a natural bypass around narrowed or blocked arteries. It has been proved that rhythms can be markers of normal functional states. Even in the absence of external perturbations, the normal heartbeat is not characterized by clockwise regularity. This fluctuation around the mean heart rate is called heart rate variability. The study was conducted on patients who had myocardial ischemia and had been prescribed enhanced external counterpulsation treatment by the physician. One of the patients was a non-ischemic heart failure patient who had heart failure secondary to dilated cardiomyopathy. Myocardial ischemia is a condition in which oxygen deprivation to the heart muscle is accompanied by inadequate removal of metabolites because of reduced blood flow or perfusion.

The study was conducted on three subject groups - 7 patients, 5 controls and 3 normals. Normals had no history of myocardial ischemia, but underwent the EECP treatment while controls were healthy and did not undergo the treatment. The subjects followed paced breathing at the rate of 12 breaths per minute. The data were collected during five minute paced breathing before and after the EECP treatment except for the controls. The waveforms of ECG, respiration and blood pressure were collected as data from the subjects. Frequency domain-power spectral analysis was performed on the data obtained using the LabVIEW 5.0 software. The time domain-SDNN analysis was also performed using MATLAB.

The results of this study fail to indicate conclusively that the EECP treatment affects the heart rate variability of the patient in a significant way. This was evidenced by conducting Power Spectral Analysis and Standard Deviation of Normal to Normal intervals on the analyzed data for the research.

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