Cardiovascular instrumentation (1975)
Type of ContentTheses / Dissertations
Thesis DisciplineElectrical Engineering
Degree NameMaster of Engineering
PublisherUniversity of Canterbury. Electrical Engineering
AuthorsBones, P. J.show all
A brief introductory treatment is made of the physiology and instrumentation of the cardiovascular system. Two areas are singled out for further investigation. Arterial blood flow is investigated. In particular the effects of atherosclerosis on the pulse wave propagation through the arterial system are considered. A method for assessing arterial condition employing two ultrasonic Doppler flowmeters is proposed. A digital zero-crossing detection system is suggested as a means of producing a relatively simple and inexpensive instrument to provide real-time results. The performance of the heart as a pump and the parameters used to assess this performance are considered. One such parameter is the cardiac ejection fraction, which relates the stroke and end-diastolic volumes of the heart's left ventricle. A new method of estimating left ventricular volume from single-plane cineangiocardiograms is described. Called the Rectangular Rule, this method approximates the volume to a series of circular discs. A special-purpose calculator has been developed to implement the Rectangular Rule and to make cardiac ejection fraction estimations. Results of studies made of patients indicate that the calculator produces results at least as accurate as those of an other popular method, and that the cardiac ejection fraction is a valuable guide to surgical prognosis.