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dc.contributor.authorMcDonagh, Theresa A.en
dc.date.accessioned2018-01-31T11:48:06Z
dc.date.available2018-01-31T11:48:06Z
dc.date.issued1999en
dc.identifier.urihttp://hdl.handle.net/1842/28571
dc.description.abstracten
dc.description.abstractThe prevalence of chronic heart failure (CHF) in most epidemiological studies has been determined by using clinical criteria.en
dc.description.abstractIn this thesis, in contrast, left ventricular systolic function was assessed objectively by echocardiography in a cross -sectional survey of 2000 men and women aged 25 -74, randomly sampled from a geographical area. Left ventricular ejection fraction (LVEF) was measured using the Biplane Simpson's Rule Method. Its aims were to document the prevalence of both symptomatic and asymptomatic left ventricular systolic dysfunction; ascertain the correlates of left ventricular systolic dysfunction; assess its effects on effort capacity; determine the usefulness of the natriuretic peptides in detecting systolic dysfunction; and to explore the possibility of a genetic component to left ventricular systolic dysfunction by examining the relationship between left ventricular systolic dysfunction and the angiotensinconverting enzyme insertion /deletion polymorphism (ACE I /D).en
dc.description.abstractIn the 1640 subjects who attended (83%), the mean left ventricular ejection fraction was 47.3%. The prevalence of `definite' left ventricular systolic dysfunction (a LVEF ≤30%) was 2.9%: it was 0.7% in men aged 35-44 years and 6.4% in men >65 years being also higher in men (4%) than women (2%). One point five percent (1.5%) had symptomatic left ventricular systolic dysfunction and 1.4% asymptomatic left ventricular systolic dysfunction.en
dc.description.abstractIn those with left ventricular systolic dysfunction, 83% had evidence of ischaemic heart disease (IHD), in contrast to 21% of those without left ventricular systolic dysfunction (p<0.001). Hypertension was more common in those with an abnormal ejection fraction (60% compared to 22%), p <0.001) but hypertension unaccompanied by IHD was not significantly more common in those with left ventricular systolic dysfunction.en
dc.description.abstractLeft systolic ventricular dysfunction was associated with a significant reduction in exercise duration. In subjects in whom this was asymptomatic there was a trend towards decreased effort capacity.en
dc.description.abstractPlasma concentrations of the natriuretic peptides were significantly higher in those with left ventricular systolic dysfunction (the median concentration (interquartile range) of N-ANP was 2.8 [1.8,4.6] ng /ml and BNP; 24 [18,33]pg/ml) than in those without (N-ANP; 1.3[0.9,1.8] ng/ml and BNP; 7.7pg/mI[3.4,13], p <0.001). The area under the Receiver Operator Characteristic Curves (SD) was greater using BNP; 0.88 (0.03) for all, 0.841 (0.03) in those with IHD, 0.86(0.03) for subjects ≥55 years and 0.84 (0.04) for those ≥55 years with IHD. The same areas under the curve for N-ANP were 0.75(0.05), 0.71(0.05), 0.72 (0.05) and 0.70 (0.06), respectively. A BNP concentration of ≥17.9pg /ml gave a sensitivity of 77% (specificity 87 %) for detecting left ventricular systolic dysfunction in all subjects, improving to 92% (specificity 72 %) when the analysis was restricted to individuals ≥ 55 with IHD.en
dc.description.abstractThe DD genotype of the ACE I/D polymorphism was significantly more common in subjects with electrocardiographic evidence of myocardial infarction (MI) or major ischaemia. (Using II as a reference, the odds ratios normal versus major ischaemia or MI were: DD 1.53, ID 1.18:p =0.03 for 10 trend). In older patients (≥51 yr.) with an ECG MI or major abnormality, LVEF was higher in those with the DD genotype (LVEF%: DD 44.6, ID 42.9, II 40;p <0.02). LVEF was also greater in older patients with a systolic blood pressure (SBP) > than the median value (LVEF%: DD 47.5, ID 45.8, Il 44.6; p= 0.012).en
dc.description.abstractThis work has shown that left ventricular systolic dysfunction is at least as twice as common than previous studies based on clinical criteria of CHF would suggest; about half is asymptomatic. Only 18% of subjects with definite left ventricular systolic dysfunction were taking an ACE inhibitor. Its main risk factors are IHD and hypertension in the presence of IHD; screening such high risk groups for left ventricular systolic dysfunction is worthy of consideration. Using a test such as BNP and targetting its use to individuals at high risk would lead to the identification of many more patients with left ventricular systolic dysfunction and, therefore, to the uptake of effective treatment. It would also lead to a more cost effective use of further investigation.en
dc.description.abstractThis thesis also provides a mechanistic insight into the development of left ventricular systolic dysfunction by suggesting that while the DD genotype confers a higher risk of MI, it is associated with better preservation of LV function post MI, possibly by enabling more adequate compensatory hypertrophy. The ACE gene I/D polymorphism may, therefore, have a bidirectional importance in determining both the risk of MI and post MI LV systolic dysfunction.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2017 Block 16en
dc.relation.isreferencedbyAlready catalogueden
dc.titlePrevalence, correlates, effects and detection of left ventricular systolic dysfunction in an urban populationen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelen
dc.type.qualificationnamePhD Doctor of Philosophyen


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