Pulmonary Hypertension (PH) is a rare but devastating illness which results in progressive right ventricular (RV) failure and early death. RV function determinessurvival in all patients with PH but it is difficult to measure accurately using existing clinical techniques. The choice and design of the experiments in this thesis wasdriven by a desire to improve our understanding of the reasons for right, and left,ventricular dysfunction in this context. Cardiovascular magnetic resonance (CMR)imaging was utilized throughout as it allows the non-invasive, direct and accurate study of both ventricles; at rest and during stress. In Chapter 3, CMR imaging was used to identify an NT-proBNP threshold (1685 ng/l, sensitivity 100%, specificity 94%) for the non-invasive detection of RV systolic dysfunction in patients with PH. In Chapter 4, contrast-enhanced-CMR was utilized for the first time in PH patients and revealed previously unidentified areas of myocardial fibrosis within the RV insertion points and interventricular septum. The extent of these areas correlated inversely with RV ejection fraction (r = -0.762, p < 0.001). Septal contrast enhancement was particularly associated with bowing of the interventricular septum.Finally, in Chapter 5, dobutamine stress-CMR was used to determine the individual reasons for right and left ventricular stroke volume impairment during exercise in PHpatients. ∆ RV stroke volume appeared limited by diminished contractile reserve as ∆ RVEF was lower in PH patients (27%) compared to controls (38%) and ∆ RVEF correlated with ∆ RV stroke volume (r = 0.94, p < 0.001). ∆ LV stroke volumeappeared limited by impaired filling, probably due to reduced LV preload as RV stroke volume and LV end-diastolic volume remained closely related at rest (r = 0.821, p < 0.001) and stress (r = 0.693, p = 0.003).
【 预 览 】
附件列表
Files
Size
Format
View
Magnetic resonance imaging of the right ventricle inhuman pulmonary hypertension
PDF
download
878987797
028-85220240
