Encyclopedia of Health and Medicine

98 The Cardiovascular System
prescribe a beta blocker for persistent PVCs, after
ruling out other cardiovascular conditions.
See also ECTOPIC BEAT; MEDICATIONS TO TREAT CAR-
DIOVASCULAR DISEASE; PALPITATIONS; SMOKING AND
HEALTH.
pulmonary arteries The large BLOOD vessels that
carry blood from the HEART to the LUNGS. The main
pulmonary ARTERY arises from the right ventricle
and immediately branches into the right and left
pulmonary arteries. The pulmonary arteries are
the only arteries in the body that transport deoxygenated
blood. Like other arteries, however, the
pulmonary arteries have sturdy, muscular walls
that rhythmically contract in synchronization with
the heartbeat. The pulmonary valve regulates the
flow of blood from the right ventricle into the pulmonary
artery.
For further discussion of the pulmonary arteries
within the context of cardiovascular structure
and function please see the overview section “The
Cardiovascular System.”
See also AORTA; VALVULAR HEART DISEASE.
pulmonary hypertension Elevated BLOOD PRES-
SURE in the PULMONARY ARTERIES and the arteries
within the LUNGS. Pulmonary HYPERTENSION develops
when the arteries in the lungs become stiff
and narrowed, increasing the resistance BLOOD
encounters in trying to flow through them. The
condition typically starts in the smallest of arteries,
the arterioles, and progressively involves larger
arteries until pressure within the pulmonary arteries
from the HEART also rises. Elevated pressure
within the pulmonary arteries increases the force
the right ventricle must exert to pump blood from
the heart to the lungs. Though early in the course
of the condition the right ventricle can compensate
by enlarging, eventually the increased workload
can lead to right HEART FAILURE.
Doctors classify pulmonary hypertension, also
called pulmonary arterial hypertension (PAH), as
either secondary or primary. Secondary pulmonary
hypertension develops as a complication of other
health conditions, notably connective tissue disorders
and chronic health conditions such as CHRONIC
OBSTRUCTIVE PULMONARY DISEASE (COPD) and PUL-
MONARY EMBOLISM. Because it follows other health
conditions that become more likely with advancing
age, secondary pulmonary hypertension tends to
occur more frequently in people over age 60.
CONDITIONS THAT CAN CAUSE
PULMONARY HYPERTENSION
AIDS
CARDIOMYOPATHY
chronic hemolytic ANEMIA CHRONIC OBSTRUCTIVE PULMONARY
COCAINE use
DISEASE (COPD)
OBSTRUCTIVE SLEEP APNEA HEART FAILURE
PULMONARY FIBROSIS
PULMONARY EMBOLISM
scleroderma
RHEUMATIC HEART DISEASE
VALVULAR HEART DISEASE SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)
Primary pulmonary hypertension (PPH) exists
independently of other health conditions and is
far less common than secondary pulmonary
hypertension. Most often doctors do not know
what causes PPH, though they believe in many
people the condition is congenital (present at
birth). Though systemic hypertension—what people
think of as high blood pressure—may damage
blood vessels throughout the body as well as damage
the heart, pulmonary hypertension and systemic
hypertension are different conditions. PPH
can affect people of any age though is more common
among people under age 50.
Symptoms and Diagnostic Path
The earliest symptom of pulmonary hypertension
is shortness of breath (DYSPNEA), typically with
exertion. As the condition progresses, symptoms
may include fatigue, SYNCOPE (fainting), chest pressure
or PAIN, peripheral edema (swelling of the
lower legs, feet, wrists, and hands), ASCITES (fluid
retention in the abdominal cavity), and PULMONARY
EDEMA (fluid accumulation in the alveoli, or air
sacs, in the lungs). Symptoms of advanced disease
often include shortness of breath at rest, CYANOSIS
(bluish hue to the SKIN and lips), and ARRHYTHMIA
(abnormal HEART RATE).
The diagnostic path begins with ELECTROCARDIO-
GRAM (ECG), which reveals right ventricular hypertrophy
(enlargement), and ECHOCARDIOGRAM, which
shows the heart’s changed structure and function.
The right ventricle typically enlarges and its walls
thicken as the pulmonary hypertension begins to
cause symptoms. Other diagnostic procedures may
include MAGNETIC RESONANCE IMAGING (MRI) for additional
visualization of the heart, PULMONARY FUNC-