Porth's Essentials of Pathophysiology, 4e

dequate perfusion of body tissues depends on the pumping ability of the heart, a vascular system to transport blood to the tissues of the body and back to the heart, sufficient blood to fill the circulatory system, and tissues that are able to extract and to use oxygen and nutrients from the blood. Heart failure and cir- culatory shock are different conditions that reflect an impairment of the circulatory system; however both conditions involve many of the same compensatory mechanisms even though they differ in terms of patho- genesis and causes. Heart Failure Heart failure is a complex syndrome resulting from functional or structural impairment of ventricular filling or ejection of blood into the circulation. 1,2 It may result from disorders of the pericardium, myocardium, endo- cardium, cardiac valves, or great vessels, or from meta- bolic abnormalities. Among the most common causes of heart failure are coronary artery disease, hypertension, dilated cardiomyopathy, and valvular heart disease. 1 Heart failure can occur in any age group but primar- ily affects the elderly; however, African Americans are disproportionately affected at a younger age. 3 Although morbidity and mortality rates from other cardiovascular diseases have decreased over the past several decades, 4 the incidence of heart failure is increasing at an alarm- ing rate. 1 This change undoubtedly reflects improved treatment methods and increased survival from other forms of heart disease. Mortality rates from heart fail- ure are variable (5% to 75% annually). 4 Once the initial diagnosis of heart failure is made, the survival rate is approximately 50% within 5 years. 1 Heart failure is associated with either a reduced or preserved left ventricular ejection fraction. Heart failure was traditionally defined as a syndrome with impaired ability of the ventricles to contract and eject blood (systolic failure with a reduced ejection fraction) or impaired ventricular relaxation (diastolic failure with a reduced end-diastolic volume). It is now recognized Heart Failure and Circulatory Shock 20 C h a p t e r A

Heart Failure Pathophysiology of Heart Failure

Cardiac Performance and Output Myocardial Contractility Compensatory Mechanisms Length-Tension/Frank-Starling Mechanism Sympathetic Nervous System Renin-Angiotensin-Aldosterone Mechanism Natriuretic Peptides Endothelins Myocardial Hypertrophy and Remodeling Types of Heart Failure Reduced versus Preserved Ejection Fraction Left-sided versus Right-sided Heart Dysfunction Manifestations of Heart Failure Fluid Retention and Edema Respiratory Manifestations Fatigue, Weakness, and Cognitive Impairment Cachexia and Malnutrition Cyanosis Arrhythmias and Sudden Cardiac Death Acute Heart Failure Syndromes

Diagnosis Treatment

Nonpharmacologic Methods Pharmacologic Treatment Oxygen Therapy Advanced Therapies

Heart Failure in the Elderly Clinical Manifestations Diagnosis and Treatment Circulatory Failure (Shock) Pathophysiology of Shock Cellular Responses

Compensatory Mechanisms

Types of Shock

Hypovolemic Shock Cardiogenic Shock Obstructive Shock Distributive Shock Complications of Shock Acute Lung Injury/Acute Respiratory Distress Syndrome Acute Kidney Injury Gastrointestinal Complications Disseminated Intravascular Coagulation Multiple Organ Dysfunction Syndrome

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