Dobutamine stress magnetic resonance imaging in tetralogy of fallot

Abstract

This thesis evaluates the role of cardiac magnetic resonance (CMR) imaging in the assessment of patients with surgically repaired tetralogy of Fallot (TOF). CMR has become a powerful tool in the serial assessment of this group of patients and provides important information on cardiac structure and function long after surgical repair. Although there are a number of long-term effects of TOF repair, chronic severe pulmonary regurgitation (PR) continues to be considered one of the most important as this has detrimental effects on cardiac function with a risk of sudden cardiac death. The optimal timing of pulmonary valve replacement remains controversial and although CMR has provided valuable information on the volumetric changes associated with chronic PR little is know about the effects of stress with pharmacological agents such as dobutamine on ventricular function and whether this can be correlated with the need for pulmonary valve intervention. Therefore, the main aim of this thesis was to determine whether dobutamine stress CMR (DS-MR) has clinical utility in TOF patients with significant PR. Through this, it has been possible to evaluate the hemodynamic and volumetric changes during DS-MR in TOF patients and how these relate to baseline characteristics. The association between great artery flow analysis and volumetric analysis in TOF patients during DS-MR has also been assessed. For comparison the DS-MR protocol was also completed in a group of healthy volunteers and this has allowed documentation of a normal volumetric and contractile reserve response to dobutamine as measured by CMR. The thesis concludes that DS-MR is safe and feasible in TOF patients and that it has potential to demonstrate early systolic ventricular impairment in these patients. Through application of DS-MR in a larger population of TOF patients it may be possible to accurately determine which patients are best suited for early pulmonary valve intervention.

Date of Award	1 Oct 2013
Original language	English
Awarding Institution	King's College London
Supervisor	Reza Razavi (Supervisor)