Date of Award


Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Dr. Lawrence S. Cohen


[From the Introduction] Since the initial attempts of Garrod to determine the duration of cardiac contraction form a recording of the radial arterial pulse, investigators have attempted to assess the functional state of the heart from externally derived records. Accurate determinations made from tracings obtained by such "noninvasive" techniques would augment the information derived from clinical history, physical examination, or electrocardiogram alone. Cardiac functional analysis might be carried out without cardiac catheterization, avoiding the associated inconveniences and morbidity associated with this "invasive" method. Repeated, periodic evaluation could be carried out on the acutely ill hospitalized patient or as a screening procedure in an outpatient population. The initial attempts to apply such external methods to assess functional response of the heart in man were performed by Bowen who demonstrated the usefulness of interpretation of the carotid pulse tracing in analysis of cardiovascular changes induced by exercise. Classic studies by Wiggers attempted to define the phases of ventricular systole. This segment of the cardiac cycle could be further subdivided. Initially he described a period of "isometric" contraction of the left ventricle prior to the opening of the aortic valve followed by a period of ejection defined as dynamic or "isotonic" systole. Katz and Feil were the first to study these subdivisions in may by use of simultaneous externally recorded tracings of electrocardiogram, phonocardiogram, and subclavian arterial pulse. Similar early studies were conducted by Lombard and Cope. The possible clinical usefulness of this noninvasive technique as an easily applied diagnostic procedure was not widely examined in the earl years of widespread cardiovascular assessment by catheterization. Definitive application of the simultaneous tracing technique, which came to be known as the measurement of Systolic Time Intervals (STI), awaited studies demonstrating the reliability and correlation of the results obtained with direct, invasively derived values.