STEPUP Cardiovascular System: Diseases of the Heart Muscle

Question 1

What is the most common type of cardiomyopathy? How does it occur? What is the prognosis?

Answer 1

1) Dilated cardiomyopathy
2) An insult (e.g., ischemia, infection, alcohol, etc.) causes dysfunction of left ventricular contractility
3) Poor prognosis - many die within 5 years of the onset of symptoms

Question 2

What is the most common cause of dilated cardiomyopathy? What are other causes?

Answer 2

1) Up to 50% of cases are idiopathic
2) Other causes include:
a) CAD (with prior MI) is a common cause
b) Toxic: Alcohol, doxorubicin, Adriamycin
c) Metabolic: Thiamine or selenium deficiency, hypophosphatemia, uremia
d) Infectious: Viral, Chagas disease, Lyme disease, HIV
e) Thyroid disease: Hyperthyroidism or hypothyroidism
f) Peripartum cardiomyopathy
g) Collagen vascular disease: SLE, scleroderma
h) Prolonged, uncontrolled tachycardia
i) Catecholamine induced: Pheochromocytoma, cocaine
j) Familial/genetic

Question 3

What are some clinical features of dilated cardiomyopathy?

Answer 3

1) Symptoms and signs of left- and right-sided CHF develop
2) S3, S4, and murmurs of mitral or tricuspid insufficiency may be present
3) Cardiomegaly is commonly seen
4) Many patients with DCM will have a coexisting arrhythmia (atrial or ventricular) related to the dilated ventricle
5) Sudden death

Question 4

How do you diagnose dilated cardiomyopathy? When is genetic testing used?

Answer 4

1) ECG, CXR, and echocardiogram results consistent with CHF

2) Genetic testing may be warranted if there is a family history of DCM and no other cause can be identified

Question 5

What is the treatment of dilated cardiomyopathy? What should you do about the offending agent? Why should anticoagulation be considered?

Answer 5

1) Similar to treatment of CHF: Digoxin, diuretics, vasodilators, and cardiac transplantation
2) Remove the offending agent if possible
3) Anticoagulation should be considered because patients are at increased risk of embolization

Question 6

How does hypertrophic cardiomyopathy occur? What is the main problem with HCM?

Answer 6

1) Most cases are inherited as an autosomal-dominant trait. However, spontaneous mutations may account for some cases
2) The main problem is diastolic dysfunction due to a stiff, hypertrophied ventricle with elevated diastolic filling pressures

Question 7

How are the elevated diastolic filling pressures in HCM further increased? What type of obstruction may also occur in HCM?

Answer 7

1) These pressures increase further with factors that increase HR and contractility (such as exercise) or decrease left ventricular filling (e.g., the Valsalva maneuver)
2) Patients may also have a dynamic outflow obstruction due to asymmetric hypertrophy of the interventricular septum

Question 8

What are symptoms of HCM? Why do arrhythmias occur? Why does cardiac failure occur? What may be the first manifestation of the disease? Can patients be asymptomatic?

Answer 8

1) Dyspnea on exertion
2) Chest pain (angina)
3) Syncope (or dizziness) after exertion or the Valsalva maneuver
4) Palpitations
5) Arrhythmias (AFib, ventricular arrhythmias) - due to persistently elevated atrial pressures
6) Cardiac failure due to increased diastolic stiffness
7) Sudden death - sometimes seen in a young athlete; may be the first manifestation of disease
8) Some patients may remain asymptomatic for many years

Question 9

What are four signs of HCM?

Answer 9

1) Sustained PMI
2) Loud S4
3) Systolic ejection murmur
4) Rapidly increasing carotid pulse with two upstrokes (bisferious pulse)

Question 10

Does the systolic ejection murmur of HCM increase or decrease with squatting, lying down, or straight leg raise and why? What about with Valsalva and standing and why? What about with sustained handgrip and why? Where is the murmur best heard?

Answer 10

1) Decreases (due to decreased outflow obstruction)
2) Increases (decreases LV size and thus increases the outflow obstruction)
3) Decreases (increased systemic resistance leads to decreased gradient across aortic valve)
4) Best heard at left lower sternal border (LLSB)

Question 11

How is the diagnosis of HCM made?

Answer 11

1) Echocardiogram establishes the diagnosis

2) Clinical diagnosis and family history

Question 12

What is the treatment for asymptomatic patients with HCM? What should all patients avoid?

Answer 12

1) Asymptomatic patients generally do not need treatment, but this is controversial. No studies have shown any alteration in the prognosis with therapy, so treatment generally focuses on reducing symptoms
2) All patients should avoid strenuous exercise, including competitive athletics

Question 13

What is the treatment for symptomatic patients with HCM?

Answer 13

1) Beta-blockers should be the initial drug used in symptomatic patients
2) Calcium channel blockers (verapamil)
3) Diuretics can be used if fluid retention occurs
4) If AFib is present, treat accordingly
5) Surgery
6) Pacemaker implantation has had variable results

Question 14

Why are beta blockers the initial drug used in symptomatic patients with HCM?

Answer 14

1) They reduce symptoms by improving diastolic filling (as HR decreases, duration in diastole increases)
2) They also reduce myocardial contractility and thus oxygen consumption

Question 15

When are calcium channel blockers (verapamil) used for treatment of HCM?

Answer 15

1) Can be used if patient is not responding to beta-blocker

2) Reduce symptoms by similar mechanism as beta-blockers

Question 16

Why is myomectomy a good option and when is it used? Is mitral valve replacement indicated for HCM?

Answer 16

1) Myomectomy has a high success rate for relieving symptoms. It involves excision of part of the myocardial septum. It is reserved for patients with severe disease
2) Mitral valve replacement is now rarely performed

Question 17

Standing and the Valsalva diminish the intensity of all murmurs except for which two? How?

Answer 17

1) MVP and hypertrophic cardiomyopathy (HCM)

2) These maneuvers decrease left ventricular volume

Question 18

Squatting and leg raise increases the intensity of all murmurs except for which two?

Answer 18

MVP and HCM

Question 19

What does sustained handgrip do to the intensity of the HCM murmur? Why?

Answer 19

1) Diminishes the intensity of the HCM murmur

2) Sustained handgrip increases systemic resistance

Question 20

What causes restrictive cardiomyopathy? When does systolic dysfunction occur? Is it more or less common than dilated or hypertrophic cardiomyopathy?

Answer 20

1) Infiltration of the myocardium results in impaired diastolic ventricular filling due to decreased ventricular compliance
2) Systolic dysfunction is variable and usually occurs in advanced disease
3) Less common

Question 21

What are causes of restrictive cardiomyopathy?

Answer 21

1) Amyloidosis
2) Sarcoidosis
3) Hemochromatosis
4) Scleroderma
5) Carcinoid syndrome
6) Chemotherapy or radiation induced
7) Idiopathic

Question 22

What are two symptoms caused by the elevated filling pressures in restrictive cardiomyopathy?

Answer 22

1) Dyspnea

2) Exercise intolerance

Question 23

Why are right-sided signs and symptoms present in restrictive cardiomyopathy?

Answer 23

Due to elevated filling pressures

Question 24

How is the diagnosis of restrictive cardiomyopathy made?

Answer 24

1) Echocardiogram
2) ECG
3) Endomyocardial biopsy may be diagnostic

Question 25

What is the size of the myocardium in restrictive cardiomyopathy? What about the RA, LA, LV, and RV sizes? In amyloidosis, what is unique about the appearance of the myocardium

Answer 25

a) Thickened myocardium and possible systolic ventricular dysfunction
b) Increased right atrium (RA) and LA size with normal LV and RV size
c) In amyloidosis, myocardium appears brighter or may have a sparkled appearance

Question 26

What are the two treatment methods of restrictive cardiomyopathy? When should you use digoxin? Why should you use diuretics and vasodilators cautiously in treating restrictive cardiomyopathy?

Answer 26

1) Treat the underlying disorder
2) Medications:
a) Give digoxin if systolic dysfunction is present (except in patients with cardiac amyloidosis, who have increased incidence of digoxin toxicity)
b) Use diuretics and vasodilators (for pulmonary and peripheral edema) cautiously, because a decrease in preload may compromise cardiac output

Question 27

What underlying disorders that cause restrictive cardiomyopathy can be treated and how?

Answer 27

1) Hemochromatosis: Phlebotomy or deferoxamine
2) Sarcoidosis: Glucocorticoids
3) Amyloidosis: No treatment available

Question 28

What is myocarditis and what are possible causes?

Answer 28

1) Inflammation of the myocardium, with many possible causes, including viruses (e.g., Coxsackie, parvovirus B19, human herpes virus-6), bacteria (e.g., group A streptococcus in rheumatic fever, Lyme disease, mycoplasma, etc.), SLE, mediations (e.g., sulfonamides); can also be idiopathic

Question 29

How does myocarditis present?

Answer 29

1) May be asymptomatic

2) May present with fatigue, fever, chest pain, pericarditis, CHF, arrhythmia, or even death

Question 30

What age and gender is the classic patient with myocarditis?

Answer 30

The classic patient is a young male

Question 31

What two laboratory studies may be elevated in myocarditis?

Answer 31

1) Cardiac enzyme levels

2) Erythrocyte sedimentation rate

Question 32

What is the treatment for myocarditis?

Answer 32

1) Treatment is supportive

2) Treat underlying causes if possible, and treat any complications