Diffusion tensor cardiovascular magnetic resonance

Heart failure with preserved ejection fraction assessed by cardiac magnetic resonance: From clinical uses to emerging techniques

Patients with heart failure with preserved ejection fraction (HFpEF) account for approximately 50% of those with heart failure (HF) and have increased morbidity and mortality when compared to those with HF with reduced ejection fraction. Currently, the pathophysiology and diagnostic criteria for HFpEF remain unclear, contributing significantly to delays in creating a beneficial and tailored treatment that can improve the prognosis of HFpEF. A multitude of studies have exclusively tested and illustrated the diagnostic value of echocardiography imaging in HFpEF; however, a widely-accepted criterion to identify HFpEF using cardiovascular magnetic resonance (CMR) imaging has not been established. As the gold standard for cardiac structural, functional measurement, and tissue characterization, CMR holds great potential for the early discovery of the pathophysiology, diagnosis, and risk stratification of HFpEF. This review aims to comprehensively discuss the diagnostic and prognostic role of CMR parameters in the setting of HFpEF through validated routine and prospective emerging techniques, and provide clinical perspectives for CMR imaging application in HFpEF.

Arrhythmogenic potential of myocardial disarray in hypertrophic cardiomyopathy: genetic basis, functional consequences and relation to sudden cardiac death

Myocardial disarray is defined as disorganized cardiomyocyte spatial distribution, with loss of physiological fibre alignment and orientation. Since the first pathological descriptions of hypertrophic cardiomyopathy (HCM), disarray appeared as a typical feature of this condition and sparked vivid debate regarding its specificity to the disease and clinical significance as a diagnostic marker and a risk factor for sudden death. Although much of the controversy surrounding its diagnostic value in HCM persists, it is increasingly recognized that myocardial disarray may be found in physiological contexts and in cardiac conditions different from HCM, raising the possibility that central focus should be placed on its quantity and distribution, rather than a mere presence. While further studies are needed to establish what amount of disarray should be considered as a hallmark of the disease, novel experimental approaches and emerging imaging techniques for the first time allow ex vivo and in vivo characterization of the myocardium to a molecular level. Such advances hold the promise of filling major gaps in our understanding of the functional consequences of myocardial disarray in HCM and specifically on arrhythmogenic propensity and as a risk factor for sudden death. Ultimately, these studies will clarify whether disarray represents a major determinant of the HCM clinical profile, and a potential therapeutic target, as opposed to an intriguing but largely innocent bystander.

Multimodality Imaging Assessment of Myocardial Fibrosis

Myocardial fibrosis, seen in ischemic and nonischemic cardiomyopathies, is associated with adverse cardiac outcomes. Noninvasive imaging plays a key role in early identification and quantification of myocardial fibrosis with the use of an expanding array of techniques including cardiac magnetic resonance, computed tomography, and nuclear imaging. This review discusses currently available noninvasive imaging techniques, provides insights into their strengths and limitations, and examines novel developments that will affect the future of noninvasive imaging of myocardial fibrosis.