Heart Failure
Heart failure (HF) can be defined as an abnormality of cardiac structure or function leading to failure of the heart to deliver oxygen at a rate commensurate with the requirements of the metabolizing tissues [1]. A multitude of inherited or acquired cardi
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Introduction to Heart Failure Heart failure (HF) can be defined as an abnormality of cardiac structure or function leading to failure of the heart to deliver oxygen at a rate commensurate with the requirements of the metabolizing tissues [1]. A multitude of inherited or acquired cardiac and extracardiac abnormalities can terminate in HF, with the most frequent causes in developed countries being coronary heart disease with ischemic injury of the myocardium (see chapter “Atherosclerotic heart disease”) and pressure overload due to hypertension (see chapter “Hypertension”). The prevalence of HF in adults is 1–2 %, rising to more than 10 % in people aged ≥70 years [1]. HF, particularly in advanced stages, is associated with an estimated lifetime cost of $110,000 per patient and year [2] and a mortality of 40 % within 5 years [1, 3]. About half of the HF patients are found to have preserved ejection fraction (HFpEF or diastolic HF) with impaired filling of the ventricle due to disturbed relaxation or increased stiffness, whereas the other half has reduced ejection fraction (HFrEF or systolic HF) [1]. Diastolic HF is often associated with higher age, female gender, hypertension
R. Pfister (*) • E. Erdmann Department III of Internal Medicine, Uniklinik Köln, Herzzentrum, Kerpener Str. 62, Köln 50937, Germany e-mail: [email protected]; [email protected]
(see chapter “Hypertension”), diabetes (see chapter “Diabetes mellitus”) and obesity, and a cardiac phenotype of hypertrophy and left atrial enlargement, whereas systolic HF is associated with male gender, coronary heart disease, and a dilated left ventricle. The major clinical issue in HF patients is fluid overload causing peripheral edema and dyspnea (shortness of breath) due to pulmonary congestion, which is caused by salt and water retention (see below).
Pathology of Heart Failure HF is progressive in nature (Fig. 1). Initially, an injury such as myocardial infarction with loss of muscle or a global contractile insufficiency due to primary cardiomyopathies or chronic overload leads to ventricular dysfunction. If dysfunction exceeds certain limits, the cardiac output will decrease leading to perceived reduction in circulating blood volume and/or pressure with insufficient perfusion of tissue. The latter activates systemic neurohumoral responses to increase tissue perfusion via vasoconstriction, retention of salt and water, and initially increase of cardiac output [4]. The key neurohumoral systems, which initiate many of these remodeling processes and hence substantially contribute to progression of HF, are the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system [1]. Albeit expedient in the acute setting, in the long term, these responses further worsen
E. Lammert, M. Zeeb (eds.), Metabolism of Human Diseases, DOI 10.1007/978-3-7091-0715-7_37, © Springer-Verlag Wien 2014
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R. Pfister and E. Erdmann
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Cardiac injury e.g. myocardial infarction
Contractility
Digitalis Diuretics Systolic output
Ventricular dysfunct
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