486
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
A
Heart Failure
and Circulatory
Shock
20
C h a p t e r
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
