C h a p t e r 2 0
Heart Failure and Circulatory Shock
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factors other than systolic failure contribute to heart failure
in the elderly. Preserved left ventricular function may be
seen in 40% to 80% of older persons with heart failure.
44
There are four changes associated with aging that
contribute to the development of heart failure in the
elderly.
44–46
First, reduced responsiveness to
β
-adrenergic
stimulation limits the heart’s capacity to maximally
increase heart rate and contractility during an increase
in activity or stress. A second major effect of aging is
increased vascular stiffness, which leads to a progressive
increase in systolic blood pressure with advancing age,
which in turn contributes to the development of left ven-
tricular hypertrophy and altered diastolic filling. Third,
in addition to increased vascular stiffness, the heart
itself becomes stiffer and less compliant with age. The
changes in diastolic stiffness result in important altera-
tions in diastolic filling and atrial function. A reduction
in ventricular filling not only affects cardiac output, but
also produces an elevation in diastolic pressure that is
transmitted back to the left atrium, where it stretches
the muscle wall and predisposes to atrial ectopic beats
and atrial fibrillation. Fourth, aging alters myocardial
metabolism at the level of the mitochondria. Although
older mitochondria may be able to generate sufficient
ATP to meet the normal energy needs of the heart, they
may be less able to respond under stress.
Clinical Manifestations
The manifestations of heart failure in the elderly often are
masked by other disease.
1,2
Nocturia or nocturnal inconti-
nence is an early heart failure symptom but may be caused
by other conditions such as prostatic hypertrophy. Lower
extremity edemamay reflect venous insufficiency. Impaired
perfusion of the gastrointestinal tract is a common cause
of anorexia and profound loss of lean body mass. Loss
of lean body mass may be masked by edema. Exertional
dyspnea, orthopnea, and impaired exercise tolerance are
cardinal symptoms of heart failure in both younger and
older persons with heart failure. However, with increasing
age, which is often accompanied by a more sedentary life-
style, exertional dyspnea becomes less prominent.
Physical signs of heart failure such as elevated jugu-
lar venous pressure, hepatic congestion, and pulmonary
crackles are less common in the elderly, in part because of
the increased incidence of diastolic failure, in which the
signs of right ventricular failure are late manifestations
and a third heart sound is typically absent.
45
Instead,
behavioral changes and altered cognition such as short-
term memory loss and impaired problem solving are
more common. With exacerbation of heart failure, the
elderly may present with acute delirium, dementia, and
restlessness. Depression is common in the elderly with
heart failure and shares the symptoms of sleep distur-
bances, cognitive changes, and fatigue.
The elderly also maintain a precarious balance
between the managed symptom state and acute symp-
tom exacerbation. During the managed symptom
state, they are relatively symptom free while adhering
to their treatment regimen. Acute symptom exacerba-
tion, often requiring emergency medical treatment, can
be precipitated by seemingly minor conditions such
as poor adherence to sodium restriction, infection, or
stress. Failure to promptly seek medical care is a com-
mon cause of progressive acceleration of symptoms.
Diagnosis andTreatment
The diagnosis of heart failure in the elderly is based on
the history, physical examination, chest radiograph, and
echocardiographic findings.
1,47
However, the presenting
symptoms of heart failure often are difficult to evalu-
ate and differentiate from changes associated with aging
and other co-morbidities. Symptoms of dyspnea on exer-
tion are often interpreted as a sign of “getting older” or
attributed to deconditioning from other diseases. Ankle
edema is not unusual in the elderly because of decreased
skin turgor and the tendency of the elderly to be more
sedentary with the legs in a dependent position.
Treatment of heart failure in the elderly involves
many of the same methods as in younger persons, with
medication dose adaptations to reduce age-related
adverse and toxic events. ACE inhibitors may be par-
ticularly beneficial to preserve cognitive and functional
capacities. Activities are restricted to a level that is
commensurate with the cardiac reserve. Seldom is bed
rest recommended or advised. Bed rest causes rapid
deconditioning of skeletal muscles and increases the
risk of complications such as orthostatic hypotension
and thromboemboli. Instead, carefully prescribed exer-
cise programs can help to maintain activity tolerance.
Even walking around a room usually is preferable to
continuous bed rest.
SUMMARY CONCEPTS
■■
Heart failure occurs when the heart fails to deliver
sufficient blood to meet the metabolic needs of
body tissues.
■■
The pathophysiology of heart failure reflects
the interplay between a decrease in cardiac
output that accompanies heart failure and the
compensatory mechanisms that preserve the
cardiac reserve. Compensatory mechanisms
include the Frank-Starling mechanism,
sympathetic nervous system activation, the
renin-angiotensin-aldosterone mechanism,
natriuretic peptides, endothelins, and myocardial
hypertrophy and remodeling. In the failing
heart, early decreases in cardiac function may
go unnoticed because these compensatory
mechanisms maintain the cardiac output.
■■
Heart failure may be described in terms of
ejection fraction (reduced vs preserved). Clinical
manifestation depends upon which ventricle is
dysfunctional. With a reduced ejection fraction,
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