Cardiomyopathies & Pericarditis

Question 1

Acute myocarditis - Etiology and Presentation

Answer 1

Acute inflammation of the cardiac muscle usually associated with immune response to viral infection (URI or GI) 2-3 weeks prior; often seen in young adults and children

Commonly presents with fever, chest pain with pericarditis-type ECG changes, arrhythmia, and heart failure

50% mortality; many survivors will develop dilated cardiomyopathies

Question 2

Which virus is most commonly associated with acute myocarditis?

Answer 2

Coxsackie virus

Question 3

Dilated cardiomyopathy - Etiology & Presentation

Answer 3

Mild hypertrophy is common but there is a greater proportional expansion in ventricular chamber volume; marked enlargement of cardiac mass - most often involves LV

Presentation - heart failure with large heart & impaired systolic function

Etiology - Usually idopathic

Question 4

Clinical Manifestations of Dilated cardiomyopathy

Answer 4

Chest film - Cardiomegaly with lung congestion

ECHO - Ventricular dilation with poor wall motion & low ejection fraction

Arrhythmia - 2/2 injury, dilation, fibrosis of normal conductive pathways; BBB common

Thromboembolism - due to poor contraction, stasis, and clotting

Question 5

Brain Natriuretic Peptide (BNP)

Answer 5

Blood marker for CHF

Good negative predictive value: BNP < 150 is probably not CHF

CHF patients have high BNP values that can be used to follow their cardiac status over time

Question 6

Hypertrophic cardiomyopathy without aortic outflow obstruction

Answer 6

Diastolic dysfunction due to impaired diastolic relaxation & increased stiffness

Elevated LV diastolic pressure causes increased pulmonary congestion - DOE is usual symptom

Question 7

Hypertrophic obstructive cardiomyopathy

Answer 7

Asymmetric myocardial hypertrophy causing diastolic dysfunction and systolic outflow obstruction

Clinical manifestations include dyspnea due to increased LV filling pressure, angina, and sudden death due to arrhythmia

Question 8

Hypertrophic obstructive cardiomyopathy - Treatment

Answer 8

Avoid extreme exertion (i.e. sports)

Decrease contractility - B-blockers/Verapamil

Surgical mymectomy

ICD implantation

Question 9

Restrictive Cardiomyopathy

Answer 9

Most often infiltrative due to amyloidosis or sarcoidosis

Impaired ventricular filling due to stiff ventricles; systolic function often normal and ventricles not usually dilated

Question 10

Most common symptoms of acute pericarditis

Answer 10

Sudden onset of chest pain - often sharp and severe

Chest pain varies with position and breathing

Question 11

Most common causes of pericarditis

Answer 11

1. Viral illness / idiopathic
2. Connective tissue or autoimmune disease
3. Uremia / renal disease
4. Metastatic malignancy

Question 12

Diagnosis of acute pericarditis

Answer 12

Acute onset of sharp, pleuritic chest pain 
Pericardial rub on cardiac exam 
ECG - Diffuse ST elevation 
ECHO - Pericardial fluid
Responds to anti-inflammatory agents

Question 13

Treatment of acute pericarditis

Answer 13

Ibuprofen, aspirin

Question 14

Pericardial effusion with tamponade

Answer 14

Caused by rapidly accumulating, moderate to large pericardial effusions; high intrapericardial pressure impairs diastolic filling

Decreased RV diastolic filling during inspiration - neck veins are distended

Paradoxical Pulse - inspiratory decrease in arterial pressure

Question 15

Paradoxical Pulse

Answer 15

Often seen with severe pericardial effusion with tamponade - signals acute emergency

Due to high intrapericardial pressure, the RV cannot expand to accomodate increased venous return during inspiration; increased RV pressure upon inspiration pushes on the septum, impinging the LV and lowering stroke volume

Question 16

Diagnosis of pericardial effusion

Answer 16

X-ray / Auscultation - Large cardiac silhouette without lung rales

ECHO - collapse of RA and RV in end diastole; dilation of the IVC which does not collapse during inspiration (signals high venous pressure)

Question 17

ECG findings of cardiac tamponade

Answer 17

Low voltage with sinus tachycardia (not specific - also seen in restrictive cardiomyopathy)

Electrical alternans with sinus tachycardia - decreased QRS amplitude with every other beat

Question 18

Constrictive Pericarditis - Causes

Answer 18

Caused by scarring & loss of elasticity of the pericardium, sometimes following cardiac surgery, radiation, or infection

Usually a chronic disease that takes considerable time to develop

Question 19

Constrictive Pericarditis - Presentation & Treatment

Answer 19

Constriction selectively impairs filling of RV - characterized by impaired diastolic filling with elevated JVP, tachycardia, hepatomegaly, edema, ascites; lungs are clear

Often mistaken for liver disease

Treated with surgical stripping of the pericardium

Question 20

Constrictive Pericarditis - ECG Findings

Answer 20

Dip and Plateau (“square root sign”) during diastole