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U N I T 5
Circulatory Function
Manifestations of Heart Failure
The manifestations of heart failure depend on the extent
and type of cardiac dysfunction that is present and the
rapidity with which it develops. A person with previ-
ously stable compensated heart failure may develop
signs of heart failure for the first time when the con-
dition has advanced to a critical point, such as with a
progressive increase in pulmonary hypertension in a
person with mitral valve regurgitation. Heart failure
also may be precipitated by conditions such as infec-
tion, emotional stress, uncontrolled hypertension, or
fluid overload.
28
Many persons with serious underlying
heart disease, regardless of whether they have previously
experienced heart failure, may be relatively asymptom-
atic as long they carefully adhere to their treatment
regimen. A dietary excess of sodium may be a cause of
sudden cardiac decompensation.
The signs and symptoms of heart failure reflect the
physiologic effects of the impaired pumping ability of
the heart, decreased renal blood flow, and activation of
sympathetic compensatory mechanisms. They include
fluid retention and edema, shortness of breath and other
respiratory manifestations, fatigue and limited exercise
tolerance, cachexia and malnutrition, and cyanosis.
Fluid Retention and Edema
Many of the manifestations of heart failure result from
the increased capillary pressures (increased hydrostatic
pressures) that develop in the peripheral and pulmonary
circulations. The increased capillary pressure reflects an
overfilling of the vascular system because of increased
sodium and water retention and venous congestion, result-
ing from impaired cardiac output.
28
Nocturia
is a nightly
increase in urine output that occurs relatively early in the
course of heart failure. It occurs because of the increased
cardiac output, renal blood flow, and glomerular filtration
rate that follow the increased blood return to the heart
when the person is in a supine position.
Oliguria,
which is
a decrease in urine output, is a late sign related to severely
reduced cardiac output and resultant renal failure.
Transudation of fluid into the pleural cavity (pleural
effusion or hydrothorax) or the peritoneal cavity (asci-
tes) may occur in persons with advanced heart failure.
Because the pleural veins drain into both the systemic
and pulmonary venous beds, hydrothorax is observed
more commonly in persons with hypertension involv-
ing both venous systems.
28
Pleural effusion occurs as the
excess fluid in the lung interstitial spaces crosses the vis-
ceral pleura, which in turn overwhelms the capacity of
the pulmonary lymphatic system. Ascites can occur in
persons with increased pressure in the hepatic and pero-
neal veins. It usually reflects right ventricular failure and
long-standing elevation of systemic venous pressure.
28
Respiratory Manifestations
Dyspnea due to congestion of the pulmonary circula-
tion is one of the major manifestations of heart failure.
Dyspnea related to activity is called exertional dyspnea;
however, patients with advanced heart failure may
experience dyspnea even at rest. Orthopnea is short-
ness of breath that occurs when a person is supine.
Gravitational forces cause fluid to become sequestered
in the lower legs and feet when the person is stand-
ing or sitting. When the person assumes the recumbent
position, fluid from the legs and dependent parts of the
body is mobilized and redistributed to an already dis-
tended pulmonary circulation. Paroxysmal nocturnal
dyspnea is a sudden attack of dyspnea that occurs dur-
ing sleep. It disrupts sleep, and the person awakens with
a feeling of extreme suffocation that resolves when he
or she sits up.
A subtle and often overlooked symptom of heart fail-
ure is a chronic dry, nonproductive cough that becomes
worse when the person is lying down. Bronchospasm
due to congestion of the bronchial mucosa may cause
wheezing and difficulty in breathing. This condition is
sometimes referred to as
cardiac asthma.
28
Sleep-disordered breathing is a common comorbid
condition with heart failure and may contribute to wors-
ening heart failure. Obstructive sleep apnea is one of the
most common forms of sleep-disordered breathing. In
persons with obstructive sleep apnea, the upper airway
collapses, which leads to the complete cessation of air-
flow (apnea) or partial cessation of air flow (hypoap-
nea) during sleep.
29
Persons with suspected obstructive
sleep apnea should be evaluated by a sleep specialist and
undergo a sleep study (polysomnography). Those who
meet the diagnostic criteria for obstructive sleep apnea
(i.e., exhibit more than five apneas/hypoapneas per hour
of sleep caused by airway obstruction) are treated by
applying continuous positive airway pressure (usually
5 to 10 cm H
2
O) during sleep. Continuous positive air-
way pressure (CPAP) is associated with reduced blood
pressure and improved cardiac function in patients with
heart disease.
29
Another abnormal respiratory pattern that may
occur with heart failure is
Cheyne-Stokes respiration
, a
pattern of periodic breathing characterized by a gradual
increase in the depth and sometimes the rate of breath-
ing to a maximum, followed by a decrease, resulting in
apnea. Although no longer associated solely with heart
failure, it is recognized as an independent risk factor for
worsening of heart failure. It has been suggested that
Cheyne-Stokes respirations may not be just a marker for
increasing severity of heart failure, but may also aggra-
vate it.
30
During sleep, Cheyne-Stokes breathing causes
recurrent awakening and thereby reduces slow-wave
and rapid eye movement (REM) sleep. The recurrent
cycling of hypoventilation/apnea and hyperventilation
may also increase sympathetic activity and predispose
to arrhythmias.
Fatigue,Weakness, and Cognitive Impairment
Fatigue and weakness often accompany diminished
output from the left ventricle. Cardiac fatigue is dif-
ferent from general fatigue in that it usually is not
present in the morning but appears and progresses as
activity increases during the day. In acute or severe
