condition as hypertrophic obstructive car-
diomyopathy (HOCM) or idiopathic hyper-
trophic subaortic stenosis (IHSS), both of which
are older terms. Hypertrophic cardiomyopathy
is hereditary, the result of mutations in a num-
ber of genes that regulate proteins essential for
myocardial cell contractions (notably myosin,
troponin T, and alpha tropomyosin). The
hypertrophy, or thickening, typically affects the
left ventricle most extensively and can involve
the ventricular septum to the extent that the
hypertrophy creates an obstruction for the
proper functioning of the aortic valve (AORTIC
STENOSIS). Undiagnosed hypertrophic cardiomy-
opathy is a leading cause of SUDDEN CARDIAC
DEATHin younger people, especially athletes.- Ischemic cardiomyopathy, which develops
secondary to longstanding IHD or following
extensive or repeated MYOCARDIAL INFARCTION.
Ischemia results from inadequate oxygen sup-
ply to the cells, some of which die. The patches
of dead muscle tissue do not contract, diminish-
ing the heart’s effectiveness. Ischemic car-
diomyopathy is more common in people over
age 60 who have other forms of cardiovascular
disease. - Peripartum cardiomyopathy,which devel-
ops in a woman during late PREGNANCYor in the
first few months after CHILDBIRTH. It appears an
inflammatory process in the body, though doc-
tors are uncertain what sets it off. In some situ-
ations there is a clear bacterial or viral
INFECTION, but most often there is no apparent
reason for the INFLAMMATION. Most women fully
recover from peripartum cardiomyopathy
though are at increased risk for developing it
again with subsequent pregnancies. - Restrictive cardiomyopathy, in which the
myocardial cells accumulate deposits that cause
them to lose elasticity. The loss restricts the
ability of the heart to expand, reducing the
ability of the ventricles to properly fill with
blood. As a consequence, the heart cannot
pump enough blood to meet the body’s needs.
Restrictive cardiomyopathy is secondary to
other health conditions such as AMYLOIDOSIS,
which leaves protein deposits, and HEMACHRO-
MATOSIS, which leaves iron deposits.
Symptoms and Diagnostic Path
Cardiomyopathy often does not show symptoms
until the condition is quite advanced, and then
the symptoms are likely to be those of other car-
diovascular conditions, such as hypertension and
heart failure, especially congestive heart failure.
Doctors commonly discover cardiomyopathy dur-
ing chest X-RAYdone for other reasons. When
symptoms are present, they typically include- shortness of breath (DYSPNEA)
- weakness and tiredness
- inability to participate in physical activities
The diagnostic path includes ELECTROCARDIO-
GRAM(ECG), which detects the arrhythmias typical
of an overworked heart, and ECHOCARDIOGRAM,
which shows the heart’s enlargement and altered
function. These tests can provide definitive diag-
nosis for most cardiomyopathy. Other diagnostic
procedures the cardiologist may recommend,
depending on the kind of cardiomyopathy sus-
pected, may include COMPUTED TOMOGRAPHY (CT)
SCAN, MAGNETIC RESONANCE IMAGING (MRI), trans-
esophageal echocardiogram (TEE), angiogram,
and myocardial biopsy. GENETIC TESTINGto detect
mutations commonly associated with hyper-
trophic cardiomyopathy can help detect the
potential for this condition before it manifests
symptoms, allowing prophylactic interventions to
delay or minimize its development.Treatment Options and Outlook
All forms of cardiomyopathy make it difficult for
the heart to pump blood effectively. Though in the
early stages of the condition the heart’s enlarge-
ment can compensate for some of the diminished
STRENGTH, eventually the compensatory measures
become ineffective and even counterproductive.
Treatment targets improving the heart’s efficiency,
usually through a combination of medications and
lifestyle modifications. Medications typically
include diuretics to reduce edema (fluid accumu-
lations), antiarrhythmia medications to maintain
the heart’s regular rhythm, vasodilator medica-
tions to relax the blood vessels and reduce resist-
ance for blood flow, and medications such as
digoxin (inotropic medications) to strengthen the
heart’s pumping effectiveness. It also is crucial to32 The Cardiovascular System