DEVELOPMENT A NUMERICAL WORKFLOW TO STUDY EFFECTS OF ATRIAL FIBRILLATION ON CARDIOVASCULAR CIRCULATION

Abstract

Atrial fibrillation (AF) is a type of supraventricular arrhythmias and one of the most common types of cardiac arrhythmia. In 2014, it was estimated that in the UK alone around 1.4 million people suffered from AF, a trend which is increasing as a result of ageing. AF can seriously impact cardiac function and subsequently it affects cardio/cerebrovascular circulation with serious complications such as heart failure, stroke, and cognitive impairments. Apart from the healthcare related issues, it imposes a massive financial burden to the patients and healthcare systems. Despite all developments in prognosis, diagnosis and treatment of AF, there are still many uncertainties regarding the underlying phenomena resulting AF and the way AF alters the haemodynamics of cardiovascular flow. In fact, AF is a complex disease and since it occurs in conjunction with other diseases, thus, its correlation with different maladies has not been fully established. Stroke is suggested as one of the frequent side effects of AF, which occurrence highly depends on flow haemodynamics. Scientists have postulated that the primary reason of stroke is clot formation in a pocket-like appendage of the left atrium (left atrial appendage) and its movement through the arterial system. However, there is some evidence suggest that the risk of thrombogenic plaques inside the aorta increases in AF patients, so, it prompts the notion of the extended effects of AF on aortic and cerebral circulations. Therefore, the present study examines effects of AF-induced poor flow circulation on aortic flow and haemodynamics throughout the vascular network. Numerical modelling and computational fluid dynamics (CFD) are prominent procedures in biofluid mechanics to explore in-isolation effects of different phenomena. The current project suggests a workflow to study AF effects on aortic circulation. Hence, 4D flow phase contrast magnetic resonance imaging (PC-MRI) along with lumped and CFD modelling techniques are employed. Then, the possible effects of AF on aortic haemodynamics, impacts of ageing, and the way AF may reduce the heart functionality are investigated. The current findings emphasise that the AF can substantially elevate thrombogenic factors in aorta, and they become more critical once the AF is accompanied by ageing. Finally, invoking the concept of exergy, the results suggest that the AF can expediate the heart ageing process.

Date of Award	1 Aug 2021
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Alistair Revell (Supervisor), Amir Keshmiri (Supervisor), Christopher Miller (Supervisor) & Josephine Naish (Supervisor)