On heart failure mechanics and hemodynamics

Heart failure is a common condition with a high burden of morbidity and mortality globally. Despite modern advancements in diagnostic evaluation and therapeutic strategies, challenges remain in providing optimal treatment for the individual patient. Heart-failure phenotyping requires imaging modalities for assessment of structures and function. This thesis is based on four studies which apply novel, in-house developed methods on cardiovascular magnetic resonance (CMR) imaging for evaluation of heart function and intraventricular blood flow.The aim was to investigate if these novel methods can improve our understanding of heart dysfunction in patients at risk for or with established heart failure, and assess the potential use as future diagnostic instruments in clinical practice. The main methods were non-invasive pressure-volume loops, and 4D-flow CMR for analysis of intraventricular kinetic energy and hemodynamic forces of the blood.The results in Study I show that non-invasive pressure-volume loops detect different responses to altered preload and afterload in patients with hypertrophic cardiomyopathy compared to in healthy participants. Study II demonstrates that in patients with precapillary pulmonary hypertension, the right ventricle acts more like a pressure pump than a volume pump, as opposed to in healthy controls. The data in Study III indicate that 4D-flow CMR may detect hemodynamic abnormalities in patients with hypertrophic cardiomyopathy, even when echocardiographic flow measurements are normal. Finally, the data in Study IV suggest that 4D flow CMR may be of value in clinical evaluation of patients with heart failure and left bundle branch block where cardiac resynchronization therapy is considered.In conclusion, novel biomarkers on CMR provide new insights in the pathophysiology of various phenotypes of heart failure, and may be of clinical value complementary to more established measures of heart dysfunction.