Pathophysiology of heart failure update: the role of neurohumoral activation in the progression of heart failure

Myofibrillar remodeling in cardiac hypertrophy, heart failure and cardiomyopathies

BACKGROUND

A wide variety of pathological conditions have been shown to result in cardiac remodelling and myocardial dysfunction. However, the mechanisms of transition from adaptive to maladaptive alterations, as well as those for changes in cardiac performance leading to heart failure, are poorly understood.

OBSERVATIONS

Extensive studies have revealed a broad spectrum of progressive changes in subcellular structures and function, as well as in signal transduction and metabolism in the heart, among different cardiovascular disorders. The present review is focused on identifying the alterations in molecular and biochemical structure of myofibrils (myofibrillar remodelling) in hypertrophied and failing myocardium in different types of heart diseases. Numerous changes at the level of gene expression for both contractile and regulatory proteins have already been reported in failing hearts and heart diseases; these changes are potential precursors for heart failure such as cardiac hypertrophy and cardiomyopathies. Myofibrillar remodelling, as a consequence of proteolysis, oxidation, and phosphorylation of some functional groups in both contractile and regulatory proteins in hearts failing due to different etiologies, has also been described.

CONCLUSIONS

Although myofibrillar remodelling appears to be associated with cardiac dysfunction, alterations in both contractile and regulatory proteins are dependent on the type and stage of heart disease.

Neurohormones and heart failure

The management of several neurohormonal pathways is crucial to treating the progression of HF, in addition to improving the quality of life for patients diagnosed with HF. Stimulation of the sympathetic and retin-angiogensin-aldosterone systems begins the initial and primary neurohormonal stimulation associated with the progression of this disease. However, it is becoming increasingly evident that other systems, including the cellular immune, endothelin-NO pathway, kallikrein-kinin system, the arachidonic acid cascade, and the natriuretic peptides need to be considered by clinicians when treating HF. Once treated solely with nitrates, diuretics, and morphine, the management of HF is becoming a more complex and intricate balancing act among several interdependent neurohormonal systems. Understanding the complex nature and proper management of these systems are crucial if patients with HF are to enjoy a better quality of life and experience an improvement in their symptoms. Current recommendations for the treatment and management of HF use several medications, which affect multiple neurohormonal pathways. The Heart Failure Society of America and the American Heart Association both recommend in their recent guidelines for management of HF the use of beta-adrenergic receptor blockers (beta-blockers), loop diuretics, digitalis glycosides(digoxin), ACE-I, aldactone antagonists (spironolactone), and in selected instances, ARBs and the combination of hydralazine and isosorbide dinitrate. No discussion of HF is complete without mention of the larger challenges associated with the management of HF. It is a complex syndrome that requires a multidisciplinary approach with expertise in nutrition, exercise, pharmacology, education, and the basic pathophysiology of complex neurohormonal systems. Patients with uncompensated HF are frightened, vulnerable, and require frequent medication adjustments as well as substantial time dedicated to counseling, physical assessment, and innovative educational programs for them and their families. In fact, a majority of hospital readmissions for HF occur because of patients' dietary indiscretions, medication noncompliance, or ignorance about when to call their health providers. The management of HF represents a careful balancing act between powerful neurohormonal pathways and medications but also between the basics of diet, exercise, educating both family and patient, and most importantly, caring.

Carnitine palmitoyltransferase-I, a new target for the treatment of heart failure: perspectives on a shift in myocardial metabolism as a therapeutic intervention

Although the heart is capable of extracting energy from different types of substrates such as fatty acids and carbohydrates, fatty acids are the preferred fuel under physiological conditions. In view of the presence of diverse defects in myocardial metabolism in the failing heart, changes in metabolism of glucose and fatty acids are considered as viable targets for therapeutic modification in the treatment of heart failure. One of these changes involves the carnitine palmitoyltransferase (CPT) enzymes, which are required for the transfer of long chain fatty acids into the mitochondrial matrix for oxidation. Since CPT inhibitors have been shown to prevent the undesirable effects induced by mechanical overload, e.g. cardiac hypertrophy and heart failure, it was considered of interest to examine whether the inhibition of CPT enzymes represents a novel approach for the treatment of heart disease. A shift from fatty acid metabolism to glucose metabolism due to CPT-I inhibition has been reported to exert beneficial effects in both cardiac hypertrophy and heart failure. Since the inhibition of fatty acid oxidation is effective in controlling abnormalities in diabetes mellitus, CPT-I inhibitors may also prove useful in the treatment of diabetic cardiomyopathy. Accordingly, it is suggested that CPT-I may be a potential target for drug development for the therapy of heart disease in general and heart failure in particular.

An ethnographic approach to understanding the illness experiences of patients with congestive heart failure and their family members

OBJECTIVE

The purpose was to understand the illness experiences of patients with congestive heart failure and their family members.

DESIGN AND SETTING

The study design was a focused ethnography that took place in 1 outpatient cardiology clinic, 2 outpatient heart failure clinics, and informants' homes located in a large metropolitan city in southeast Texas.

SAMPLE

The sample consisted of 28 informants (patients, n = 16; family members, n = 12).

METHOD

Data were collected from observations, participant observations, demographic forms, chart reviews, and interviews. Interviews were open-ended, semistructured, in-depth, and audiotaped. A thematic analysis process was conducted through domain analysis and constructing data into themes and subthemes.

FINDINGS

Patients with congestive heart failure and their family members experience a process of disruption, incoherence, and reconciling. Reconciling emerged as the salient experience described by informants and was manifested as struggling, participating in partnerships, finding purpose and meaning in the illness experiences, and surrendering.

Clinical practice guidelines: necessary but not sufficient for evidence-based patient education and counseling

While clinical practice guidelines provide direction for the management of specific diseases or particular clinical problems, there are major gaps between guidelines and their implementation. The purpose of this paper is to illustrate how an existing guideline can be used to develop an evidence-based patient education program. Congestive heart failure (CHF) represents a range of complex, chronic illnesses which offer little hope of cure yet require symptom management by health care providers, patients, and their families. Successful self-monitoring, self-care, and decision making are based on acquisition of appropriate knowledge and management skills. We describe a comprehensive teaching program in which the content was built on the clinical evidence from the Agency for Health Care Policy and Research recommendations for CHF, and the implementation process was built on adult education evidence, adapted to health issues and patient learning challenges.

Outcome measurement: self-management in heart failure

Improvement in heart failure outcomes depend on patients' abilities to care for themselves and manage aspects of their condition, and patient self-management has itself become an outcome to be measured. Some behaviors, such as diet and fluid restriction, are prescribed, and self-management is often equated with adherence to the treatment regimen. Self-management has also been defined as cognitive decision making in response to symptoms and conceptualized as a process with stages from novice to expert. Greater understanding and measurement of patient decision making and self-management expertise facilitates the development of effective interventions to improve patient outcomes.

Understanding cytokines. Part II: Implications for nursing research and practice

Cytokines are small signaling proteins released from a variety of cells that influence virtually every aspect of growth and development and every host response to infection, injury, and inflammation. Because of their widespread and potent effects across the life span, cytokines without a doubt influence nursing research and practice. From physiological and adaptive effects of cytokines to cytokine-induced diseases, nurses and nursing care are involved. Part II of this review highlights a few of the many examples of cytokines functioning in response to infection and inflammation, during the processes of reproduction, and in a variety of pathophysiological states. Implications for nursing research and practice are emphasized.