Cardiomyopathies and primary myocardial diseases

Question 1

Cardiomyopathies

Answer 1

any age, disease of the myocardium–causes the heart to become enlarged and dilated, thickened, and or stiffened, weakens the heart causing it to become inefficient and incapable of pumping blood and maintaining a normal rhythm, this can lead to heart failure, arrhythmia or sudden death

Question 2

3 patterns types of cardiomyopathies based on clinical functional and pathologic features

Answer 2

Dilated cardiomyopathy (DCM)- most common 90%
Hypertrophic cardiomyopathy (HCM)
Restrictive cardiomyopathy (RCM)- least common

Question 3

Dilated cardiomyopathy (DCM)

Answer 3

1 in 2700, accounts for 10k deaths and 46k hospitalizations yearly in the US
Primary indication of cardiac transplantation, clinical onset usually occurs in the adult years

Progressive cardiac dilataion and contractile (systolic) dysfunction of both ventricles, usually with concomitant hypertrophy and eventually heart failure (leads to cardiomegaly 2-3x normal weight globular appearance)

four chamber dilatation, flabby, mural thrombi, valves are normal but mitral or tricuspid regurgitation may be present due to dilation of chamber (functional regurgitation)

Question 4

Dilated cardiomyopathy clinical features

Answer 4

CHF: edema, orthopnea (inability to breathe except in upright position), paroxysmal nocturnal dyspnea (caused by lung congestion occuring suddenly at night)

Reduced cardiac output (fatigue, dyspnea on exertion)

Arrhythmias and or conduction system disease, thromboembolic disease, occasionally muscle weakness or dystrophy
Diganosis: imagind DKG, biopsy

ALcohol, infection (cosackie B), iron overload, peripartum cardiomyopathy (late in gestation up to several weeks) multifactorical

Titin TTN familial DCM mutation , X linked

Question 5

Hypertrophic cardiomyopathy

Answer 5

Leading cause of sudden cardiac death (SCD) in the young and most common cause of SCD in young athletes

Unexplained left ventricular hypertrophy in the absence of another cardiac or systemic disease

Gross morphology: massive myocardial hypertrophy, Banana septum, no ventricular dilatation, ventricle compressed

Atrium enlarged (due to decreased ventricular compliance)
Endocardial thickening and mural plaques in the outflow tract, valve contacting septum during contraction 

Chest pain, exertion-related dyspnea, or syncope, atrial fibrillation with mural thrombus formation, heart failure or unexpected SCD, sudden death, majority of individuals remain asymptomatic

Question 6

Arrhthmogenic right ventricular dysplasia/ cardiomyopathy (ARVD/C)

Answer 6

progressive disorder affecting RV, characterized by transmural fibrofatty replacement of the RV myocardium, predisposing to ventricular tachycardia and sCD

Most common features are heart palpitations, syncope and death

Present in 4-22% of athletes with SCD (high intensity exercise can exacerbate development of ARVD/C

Question 7

restrictive cardiomyopathy

Answer 7

rare, unknown prevalence, normal LV wall thickness and ejection fraction

Primary decrease in compliance –> ventricular filling during diastolu

Overlaps with DCM and HCM

bi atrial dilation, firm myocardium and interstitial fibrosis

Histology- patchy or diffuse interstitial fibrosis and disease specific changes

Question 8

RCM clinical features

Answer 8

CHF (right and left sided)- sever pulmonary congestion, hepatic congestion

Similar S/S as constrictive pericarditis

Cardiac conduction system disease, heart block resulting from focal fibrosis of CCS
Possible skeletal myopathy

Question 9

RCM Etiology

Answer 9

Secondary to post radiation fibrosis, amyloidosis, sarcoidosis, metastases, Fabry disease, pompe

Endomyocardial fibrosis: childeren and young adults in africa, fibrosis of ventricular endocardium and subendocardium–>diminished volume and compliance–>restrictive mural thrombi

Question 10

Cardiac amyloidosis

Answer 10

collection of disease in which a protein based infiltrate deposits in tissues as beta pleated sheets (subtype depends on which protein is depositing)

Senile cardiac amyloidosis: most common (transthyretin prealbumin)-deposits in ventricles and atria, >60 yrs age african americans more

Systemic AA or AL amyloidosis may also involve the heart

Restrictive hemodynamics (asymptomatic, pressure atrophy of fibers, deposition in region of conduction system leads to arrhythmias)

HF, dyspnea, edema