2. CARDIOMYOPATHY
• Cardiomyopathy is a group of diseases that affect the
heart muscle.
• Types of cardiomyopathy include hypertrophic
cardiomyopathy, dilated cardiomyopathy, restrictive
cardiomyopathy, arrhythmogenic right ventricular
dysplasia, and takotsubo cardiomyopathy (broken heart
syndrome).
3.
4. DEFINITION
• Hypertrophic cardiomyopathy (HCM) is a condition in
which a portion of the heart becomes thickened without
an obvious cause.
• This results in the heart being less able to pump blood
effectively.
7. • Hypertrophic cardiomyopathy also can affect the heart's
mitral valve, causing blood to leak backward through the
valve.
• Sometimes, the thickened heart muscle doesn't block
blood flow out of the left ventricle.
• This is referred to as non-obstructive hypertrophic
cardiomyopathy.
8. • In both obstructive and non-obstructive HCM, the
thickened muscle makes the inside of the left ventricle
smaller, so it holds less blood.
• The walls of the ventricle may stiffen, and as a result, the
ventricle is less able to relax and fill with blood.
• This can raise blood pressure in the ventricles and the
blood vessels of the lungs. Changes also occur to the
cells in the damaged heart muscle, which may disrupt the
heart's electrical signals and lead to arrhythmias.
9.
10. ETIOLOGY
• Familial hypertrophic cardiomyopathy is inherited as an
autosomal dominant trait and is attributed to mutations in
one of a number of genes that encode for the sarcomere
proteins.
• Long-term high blood pressure.
• Heart tissue damage from a heart attack.
• Chronic rapid heart rate.
• Heart valve problems.
• Metabolic disorders, such as obesity, thyroid disease or
diabetes.
11. PATHOPHYSIOLOGY
• In the most common phenotype, the anterior septum and
contiguous anterior free wall below the aortic valve are
markedly hypertrophied and thickened, with little or no
hypertrophy of the left ventricular (LV) posterior wall.
• Sometimes isolated apical hypertrophy occurs; however,
virtually any asymmetric pattern of left ventricular
hypertrophy can be observed, and in a small minority of
patients even symmetric hypertrophy has been noted.
12. • Hypertrophy results in a stiff, noncompliant chamber
(usually the left ventricle) that resists diastolic filling,
elevating end-diastolic pressure and thus increasing
pulmonary venous pressure. As resistance to filling
increases, cardiac output decreases, an effect worsened
by any outflow tract gradient present. Because
tachycardia allows less time for filling, symptoms tend to
appear mainly during exercise or tachyarrhythmias.
13. • Coronary blood flow may be impaired, causing angina
pectoris, syncope, or arrhythmias in the absence of
epicardial coronary artery disease (CAD).
• Flow may be impaired because capillary density relative
to myocyte size is inadequate (capillary/myocyte
imbalance) or lumen diameter of intramyocardial coronary
arteries is narrowed by intimal and medial hyperplasia
and hypertrophy.
14.
15. SIGNS AND SYMPTOMS
• Could be asymptomatic
• Shortness of breath
• Exertional chest pain
• Heart palpitations
• Lightheadness, fainting, weakness/ syncope
• Sudden cardiac death
• Usually the onset is between 20-40 years.
16. RISK FACTORS FOR SUDDEN DEATH
• History of cardiac arrest and ventricular fibrillation
• Ventricular tachycardia
• Family of premature sudden death
• Unexplained syncope
• Abnormal blood pressure
19. • Diagnosis is suspected based on a typical murmur and
symptoms. Suspicion is increased if the patient has a
history of unexplained syncope or a family history of
unexplained sudden death. Unexplained syncope in young
athletes should always raise suspicion. Hypertrophic
cardiomyopathy must be distinguished from aortic stenosis
and coronary artery disease, which cause similar
symptoms.
20.
21. • ECG and 2-dimensional echocardiography and/or MRI (the
best noninvasive confirmatory tests) are done.
• Chest x-ray is often done but is usually normal because
the ventricles are not dilated (although the left atrium may
be enlarged). Patients with syncope or sustained
arrhythmias should be evaluated as inpatients. Exercise
testing and 24-hour ambulatory monitoring may be helpful
for patients considered at high risk, although accurately
identifying such patients is difficult.
22. • The ECG usually shows voltage criteria for LV hypertrophy
(eg, S wave in lead V1 plus R wave in lead V5 or V6 > 35
mm).
• Very deep septal Q waves in leads I, aVL, V5, and V6 are
often present with asymmetric septal hypertrophy;
hypertrophic cardiomyopathy sometimes produces a QRS
complex in V1 and V2, simulating previous septal infarction.
T waves are usually abnormal; the most common finding is
deep symmetric T-wave inversion in leads I, aVL, V5, and
V6.
23. • ST-segment depression in the same leads is common
(particularly in the apical obliterative form). The P wave is
often broad and notched in leads II, III, and aVF, with a
biphasic P wave in leads V1 and V2, indicating left atrial
hypertrophy. Incidence of preexcitation phenomenon of
the Wolff-Parkinson-White syndrome type, which may
cause palpitations, is increased. Bundle branch block is
common.
24. Classic HCM pattern with asymmetrical septal hypertrophy
Voltage criteria for left ventricular hypertrophy.
Deep narrow Q waves < 40 ms wide in the lateral leads I, aVL and V5-6.
This ECG was taken from a 30-year old man who presented with
exertional lightheadedness and palpitations. The ECG was misread by
the cardiology team as showing “left ventricular hypertrophy, lateral
infarct age undetermined”.
The patient was discharged home and subsequently died of a VF arrest
while running to catch a bus. Autopsy showed septal hypertrophy
consistent with HCM.
25. • Cardiac magnetic resonance imaging (CMR), considered
the gold standard for determining the physical properties
of the left ventricular wall, can serve as an alternative
screening tool when an echocardiogram provides
inconclusive results.
26.
27. • Cardiac catheterization is usually done only when
invasive therapy is considered. Usually, no significant
stenosis are present in the coronary arteries, but older
patients may have coexisting CAD.
• Genetic markers do not influence treatment or identify
high-risk individuals. However, genetic testing may be of
benefit in screening family members.
28. PROGNOSIS
Overall, annual mortality is about 1% for adults but is
higher for children. Death is usually sudden, and sudden
death is the most common sequelae; chronic heart failure
occurs less often. A higher risk of sudden cardiac death is
predicted by the presence of the following risk factors:
• Family history of sudden cardiac death due to
hypertrophic cardiomyopathy
• Unexplained recent syncope
29. • Multiple repetitive non-sustained ventricular tachycardia
(on ambulatory ECG)
• Hypotensive or attenuated blood pressure response to
exercise
• Massive left-ventricular hypertrophy (thickness ≥ 30 mm)
• Extensive and diffuse late gadolinium enhancement on
MRI
30. TREATMENT
• Beta-blockers
• Rate-limiting and negative inotropic calcium channel
blockers
• Avoidance of nitrates, diuretics, and angiotensin-
converting enzyme (ACE) inhibitors
• Possibly antiarrhythmics (eg, disopyramide, amiodarone)
• Possibly implantable cardioverter-defibrillator and
sometimes surgery or ablative procedures
31.
32. • Treatment of hypertrophic cardiomyopathy is based on the
phenotype. Patients without obstruction generally have a
stable clinical course without significant symptoms, although
some experience heart failure symptoms due to diastolic
dysfunction.
• Beta-blockers and heart rate-limiting calcium channel
blockers with a lower arterial dilation capacity (usually
verapamil), alone or combined, are the mainstays. By
slowing the heart rate, they prolong the diastolic filling
period, which may increase left ventricular filling in patients
with diastolic dysfunction. Long-term efficacy of such
therapy, however, has not been proven.
33. • Avoid nitrates and other drugs that decrease preload (eg,
diuretics, angiotensin-converting enzyme inhibitors,
angiotensin II receptor blockers) because these decrease
left ventricular size and worsen left ventricular function.
34.
35. If syncope or sudden cardiac arrest has occurred or if ventricular
arrhythmia is confirmed by ECG or 24-hour ambulatory monitoring,
an implantable cardioverter-defibrillator (ICD) should usually be
placed. Controversy exists regarding the need to place a
defibrillator in patients without syncope, sudden cardiac arrest, or
ventricular arrhythmias. It is generally believed that ICD insertion
should be considered in patients with high-risk features, which
include
• A family history of premature sudden cardiac arrest
• Left ventricular wall thickness > 3 cm
• Abnormal blood pressure response on exercise treadmill testing
(fall in systolic pressure of > 10 mm Hg)
• Left ventricular outflow tract obstructive gradient of > 50 mm Hg
• Delayed enhancement on cardiac MRI
36. PREVENTION
• Maintain a healthy, well-balanced diet
• Limit alcohol intake or abstain from drinking altogether
• Quit smoking
• Manage stress
