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VO2peak/THV-ratio differ between heart failure patients with preserved ejection fraction and healthy controls
Kristianstad University, School of Education and Environment.
2017 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

Heart failure is a term for a group of complex symtoms characterized by reduced heart function. One of these syndromes, referred to as heart failure with preserved ejection fraction (HFpEF), has increased in prevalence compared to other types of heart failures during the recent years. A concern is the difficulty in diagnosing patients with HFpEF, since current tools are considered insufficient. The aim of this thesis was to examine Peak Oxygen Uptake (VO2peak) in relation to Total Heart Volume (THV) among heart failure patients with preserved ejection fraction (HFpEF, EF >40 %) compared to healthy controls. THV was acquired by delineating images acquired using cardiovascular magnetic resonance imaging, while VO2peak was measured in oxygen curves acquired from cardiopulmonary exercise tests. Ratios were calculated by dividing VO2peak with THV. In order to determine if blood hemoglobin concentration (b-Hb) could affect the ratio, ratios were adjusted to b-Hb using an adjusting factor. Mean THV was nearly 250 ml larger in HFpEF patients compared to the controls. Patients’ mean VO2peak was more than 1000 ml lower compared to the controls. Mean VO2peak/THV ratio calculated for the patients were less than half of that calculated for the controls. Adjusting the ratio to b-Hb did not affect the ratios significantly. The study was limited by the size of the test group, but the findings suggest that a VO2peak/THV ratio can be used to separate HFpEF patients from healthy controls.

Abstract [sv]

Hjärtsvikt är ett begrepp för en grupp med komplexa symtom och kännetecknas av försämrad hjärtfunktion. Ett av dessa syndrom, hjärtsvikt med bevarad ejektionsfraktion (HFpEF), har ökat i prevalens jämfört med andra varianter av hjärtsvikt under de senaste åren. Ett problem är de svårigheter som finns med att diagnosticera patienter med HFpEF, då nuvarande verktyg inte är tillräckliga. Syftet med detta examensarbete var att undersöka maximalt syreupptag (VO2peak) i förhållande till total hjärtvolym (THV) bland hjärtsviktspatienter med bevarad ejektionsfraktion (HFpEF, EF >40 %) jämfört med friska kontroller. THV erhölls genom att utlinjera bilder tagna med hjälp av magnetisk resonanstomografi, medan VO2peak mättes i syrevolymkurvor som registrerats under ergospirometri-undersökningar. Index beräknades genom att dividera VO2peak med THV. För att undersöka huruvida halten hemoglobin i blodet (b-Hb) kunde påverka index justerades index mot b-Hb med hjälp av en justeringsfaktor. Medel-THV var nästan 250 ml större hos HFpEF-patienter jämfört med kontroller. Medel-VO2peak var mer än 1000 ml lägre hos patienterna jämfört med kontroller. Medel VO2peak/THV-index som beräknats för patienter var mindre än hälften så högt som index beräknat för kontroller. Att justera index mot b-Hb påverkade inte index signifikant. Studien begränsades av mängden deltagare, men fynden indikerar att VO2peak/THV-index kan användas för att skilja HFpEF-patienter från friska kontroller.

Place, publisher, year, edition, pages
2017. , p. 22
Keyword [en]
Heart failure, Magnetic Resonance Imaging, Cardiovascular Magnetic Resonance Imaging, Preserved Ejection Fraction, Total Heart Volume, Peak Oxygen Uptake, VO2peak/THV ratio
Keyword [sv]
Hjärtsvikt, magnetresonanstomografi, kardiovaskulär magnetresonanstomografi, bevarad ejektionsfraktion, total hjärtvolym, maximalt syreupptag, VO2peak/THV -index
National Category
Biomedical Laboratory Science/Technology Cardiac and Cardiovascular Systems
Identifiers
URN: urn:nbn:se:hkr:diva-17863OAI: oai:DiVA.org:hkr-17863DiVA, id: diva2:1181471
Educational program
Bachelor of Science in Biomedical Laboratory Science
Supervisors
Examiners
Available from: 2018-02-14 Created: 2018-02-08 Last updated: 2018-02-14Bibliographically approved

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Biomedical Laboratory Science/TechnologyCardiac and Cardiovascular Systems

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