The Impact of Myocardial Infarction on Ventricular Function

McGhie, Arthur Iain (1990) The Impact of Myocardial Infarction on Ventricular Function. MD thesis, University of Glasgow.

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Abstract

Eighty one patients were studied using radionuclide ventriculography to study the effects of myocardial infarction (36 anterior and 45 inferior) on ventricular function during the early and convalescent phases. Left and right ventricular function was assessed during hospitalisation on day 1, day 3 and at hospital discharge and repeated after a mean of 16+/-3 months following the index infarction. Chapter 1 is a review of the literature relating to the impact of acute myocardial infarction on ventricular function. This chapter is in 3 sections; the first two deal with the effects of myocardial infarction on global and regional left ventricular function, respectively, and the final section relates to the natural history of right ventricular function following myocardial infarction. Within each section the findings from animal experiments and early haemodynamic studies are reviewed first, followed by the findings of clinical studies which have mainly utilised non-invasive techniques to assess ventricular function. Chapter 2, "Methods", contains the details of the patient population studied, study design, statistical methods and the radionuclide techniques employed. Details regarding the use of Xenon-133 in the evaluation of right ventricular function and the analysis of regional ventricular function are dealt with in later chapters. Chapter 3, "The impact of acute myocardial infarction on global left ventricular function", presents the findings from the analysis of global left ventricular function during the hospitalisation phase. Anterior myocardial infarction was associated with lower ejection fractions than inferior myocardial infarction. Little variation was found in the left ventricular ejection fraction when patients were grouped according to the site of infarction. Variability in the left ventricular ejection fraction was found to occur in certain individuals and some patient subgroups. This did not appear to be related to any of the measured patient demographics or prognosis. A good correlation was found between the left ventricular ejection fraction and the size of infarction as estimated by Tl-201 scintigraphy. The correlation between the left ventricular ejection fraction and the enzymatic estimate of infarct size was closer following anterior in comparison with inferior infarction. The Killip and Norris classifications were not closely related to the left ventricular ejection fraction. A low left ventricular ejection fraction was associated with increased mortality; in addition the relationship between the left ventricular ejection fraction and mortality appeared to be influenced by the site of infarction. Chapter 4, "The impact of acute myocardial infarction on right ventricular function", deals with the data pertaining to right ventricular function obtained from gated technetium-99m equilibrium ventriculography during the hospitalisation phase. Right ventricular dysfunction was identified in 64% and 39% of patients following inferior and anterior infarction, respectively. No significant change in the right ventricular ejection fraction occurred following either anterior or inferior infarction during this period. Chapter 5, "Assessment of right ventricular function following acute inferior myocardial infarction using 133-Xenon imaging", presents the findings from the use of gated 133-Xenon imaging to assess right ventricular function acutely following acute inferior myocardial infarction. The use of this techniques overcomes many of the limitations of other techniques in the assessment of right ventricular function. Acute inferior myocardial infarction was found to result in a wide spectrum of right ventricular dysfunction. The right ventricular ejection fraction ranged from 7-54%, mean 30+/-11%. The findings were compared to clinical assessment of right ventricular function, and revealed that significant right ventricular dysfunction often goes undetected clinically. Chapter 6, "The natural history of ventricular function in the sixteen months following acute myocardial infarction", examines the course of left and right ventricular function during the convalescent phase (mean follow-up period 16+/-3 months). A slight improvement was observed in the left ventricular ejection fraction following inferior myocardial infarction. Chapter 8, "The relationship between the left ventricular ejection fraction and regional ventricular function", examines the relationship between alterations in the left ventricular function and regional ventricular function using the technique described in Chapter 7. No change was found in regional ventricular function following anterior myocardial infarction during the in-hospital phase. Chapter 9, "The impact of myocardial infarction on ventricular function", reviews the subject of ventricular function following myocardial infarction with reference to the major findings presented in this thesis and possible areas for future study are discussed.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: Medicine
Date of Award: 1990
Depositing User: Enlighten Team
Unique ID: glathesis:1990-78121
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 15:40
Last Modified: 30 Jan 2020 15:40
URI: http://theses.gla.ac.uk/id/eprint/78121

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