EKG, Vector Cardiograms & PulseWave Velocity
Abstract
EKG recordings can provide valuable information in diagnosing patient heart function, dysfunction and disease along with function or dysfunction of the autonomic nervous system. This lab explored the setup of a simple 4 lead EKG, recording of EKG lead signals, calculation of mean QRS and creation of 2D & 3D Vector Cardiograms. By varying posture, body orientation, physical strain, and oxygen supply among other maneuvers, modulations of both the morphological profile of the heart and the stimulation of the parasympathetic and sympathetic nervous systems were achievable. Resultant changes in EKG were analyzed. By using force transducers on both the finger and toe and a simultaneous EKG recording, pulse wave velocity measurements were obtained for both the path from heart to finger or toe and the path from finger to toe. Statistical analysis was performed on a small group of 23 subjects resting, max,min and equilibrium heart rates while standing, but the sample size was too small to show normal distribution. Resultant data demonstrated that VCGs are a viable method of detecting changes in heart morphology and depolarization pathways, while a simple 3 lead EKG can suffice for calculating meanQRS vectors. It was found that stimulants of the parasympathetic nervous system slowed the heart rate,including vagal stimulation and inspiration. Results on changes in PWV in response to different maneuvers were for the most part inconclusive due to small relative changes in PWV and self-defeating data.
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