Microvascular Dysfunction across the Spectrum of Heart Failure Pathology: Pathophysiology, Clinical Features and Therapeutic Implications.

Coronary microvascular dysfunction (CMD) plays a crucial role across the spectrum of heart failure (HF) pathology, contributing to disease development, progression, and outcomes. The pathophysiological mechanisms linking CMD to HF are complex and still not completely understood and include chronic inflammation, oxidative stress, and neurohormonal activation. Despite the diagnostic and prognostic relevance in patients with HF, there is no specific therapeutic strategy targeting CMD to date. Moreover, the diagnosis of this clinical condition is challenging. In this review article, we aim to discuss the different clinical pathogenetic mechanisms linking CMD to HF across the different spectra of these diseases, their prognostic relevance, and the possible therapeutic targets along with the remaining knowledge gaps in the field.

Basic science of cardiac contractility modulation therapy: Molecular and electrophysiological mechanisms.

In heart failure with reduced ejection fraction and heart failure with preserved ejection fraction, profound cellular and molecular changes have recently been documented in the failing myocardium. These changes include altered calcium handling and metabolic efficiency of the cardiac myocyte, reactivation of the fetal gene program, changes in the electrophysiological properties of the heart, and accumulation of collagen (fibrosis) at the interstitial level. Cardiac contractility modulation therapy is an innovative device-based therapy currently approved for heart failure with reduced ejection fraction in patients with narrow QRS complex and under investigation for the treatment of heart failure with preserved ejection fraction. This therapy is based on the delivery of high-voltage biphasic electrical signals to the septal wall of the right ventricle during the absolute refractory period of the myocardium. At the cellular level, in patients with heart failure with reduced ejection fraction, cardiac contractility modulation therapy has been shown to restore calcium handling and improve the metabolic status of cardiac myocytes, reverse the heart failure-associated fetal gene program, and reduce the extent of interstitial fibrosis. This review summarizes the preclinical literature on the use of cardiac contractility modulation therapy in heart failure with reduced and preserved ejection fraction, correlating the molecular and electrophysiological effects with the clinical benefits demonstrated by this therapy.

The Liver in Heart Failure: From Biomarkers to Clinical Risk.

Heart failure (HF) is a clinical syndrome due to heart dysfunction, but in which other organs are also involved, resulting in a complex multisystemic disease, burdened with high mortality and morbidity. This article focuses on the mutual relationship between the heart and liver in HF patients. Any cause of right heart failure can cause hepatic congestion, with important prognostic significance. We have analyzed the pathophysiology underlying this double interaction. Moreover, we have explored several biomarkers and non-invasive tests (i.e., liver stiffness measurement, LSM) potentially able to provide important support in the management of this complex disease. Cardiac biomarkers have been studied extensively in cardiology as a non-invasive diagnostic and monitoring tool for HF. However, their usefulness in assessing liver congestion in HF patients is still being researched. On the other hand, several prognostic scores based on liver biomarkers in patients with HF have been proposed in recent years, recognizing the important burden that liver involvement has in HF. We also discuss the usefulness of a liver stiffness measurement (LSM), which has been recently proposed as a reliable and non-invasive method for assessing liver congestion in HF patients, with therapeutic and prognostic intentions. Lastly, the relationship between LSM and biomarkers of liver congestion is not clearly defined; more research is necessary to establish the clinical value of biomarkers in assessing liver congestion in HF patients and their relationship with LSM.

Measurement of Cardiac-Specific Biomarkers in the Emergency Department: New Insight in Risk Evaluation.

The aim of this article review is to analyze some models and clinical issues related to the implementation of accelerated diagnostic protocols based on specific cardiac biomarkers in patients admitted to the emergency department (ED) with symptoms compatible with acute cardiac disorders. Four specific clinical issues will be discussed in detail: (a) pathophysiological and clinical interpretations of circulating hs-cTnI and hs-cTnT levels; (b) the clinical relevance and estimation of the biological variation of biomarkers in patients admitted to the ED with acute and severe diseases; (c) the role and advantages of the point-of-care testing (POCT) methods for cardiac-specific biomarkers in pre-hospital and hospital clinical practice; and (d) the clinical role of specific cardiac biomarkers in patients with acute heart failure (AHF). In order to balance the risk between a hasty discharge versus the potential harms caused by a cardiac assessment in patients admitted to the ED with suspected acute cardiovascular disease, the measurement of specific cardiac biomarkers is essential for the early identification of the presence of myocardial dysfunction and/or injury and to significantly reduce the length and costs of hospitalization. Moreover, specific cardiac biomarkers (especially hs-cTnI and hs-cTnT) are useful predictors of mortality and major adverse cardiovascular events (MACE) in patients admitted to the ED with suspected acute cardiovascular disease. To guide the implementation of the most rapid algorithms for the diagnosis of Non-ST-Elevation Myocardial Infarction (NSTEMI) into routine clinical practice, clinical scientific societies and laboratory medicine societies should promote collaborative studies specifically designed for the evaluation of the analytical performance and, especially, the cost/benefit ratio resulting from the use of these clinical protocols and POCT methods in the ED clinical practice.