Myocarditis/ Cardiomyopathy

Question 1

1. Explain the theory proposed for myocyte injury in acute viral myocarditis.

Answer 1

viral infection causes myocyte necrosis and macrophage activation which causes cytokine expression and an inflammatory response

Question 2

2 Differentiate the roles of direct viral injury, injury due to inflammation and secondary effects caused by the immune system on myocytes in the pathophysicology of viral myocarditis

Answer 2

macrophage activation causes an infiltration of monouclear cells and cytokine expression incites natural killer cells in the viral clearing phase

Question 3

3. Describe the basic genetic abnormailities that result in hypertrophic cardiomyopathy.

Answer 3

1/500 people have autosomal dominant, mutations are in sarcomeric proteins; most common myosin heavy chain (beta myosin mutation aparent by age 20, tropnin T by age 40, myosin binding protein C by age 60

Question 4

4. Describe the clinical presentation of hypertrophic cardiomyopathy.

Answer 4

disproportionate and inapporpriate hypertrophy of the LV, often septum is invovled (asymmetric septal hypertrophy) which leads to diastolic dysfunction

Question 5

5. Explain how the hemodynamic abnormailites associated with hypertrophic cardiomyopathy may limit exercise capacity.

Answer 5

hypderdynamic systolic function, impaired relaxation and increased stiffness, arrhthmogenicity (fibrosis) mitral valve apparatus dysfunction— lead to lesser cardiac output which worsens with exercise

exercise can increase preload which will worsen symptoms

Question 6

6. Contrast the structural abnormalities of dilated cardiomyopathy with hypertrophic cardiomyopathy.

Answer 6

dilated abnormalities are connected to abnormalities in cytoskeleton while hypertrophic cardiomyopathy is due to mutations in the sarcomeric proteins

Question 7

What are the three current theories regarding the damage during chronic phase of myocarditis.

Answer 7

chronic immune activation (cytotoxic T ; persistent viral infection, virus-induced apoptosis

Question 8

Describe the clinical presentation and treatment for myocarditis.

Answer 8

viral syndrome (fatigue, fever, myalgias) chest pain, dyspnea, palpitations, syncope and sudden cardiac death; tx. Within 24 hrs with antivirals, immunosuppression , and bed rest with Bblockers and ACEI

Question 9

Describe the signs that accompany hypertrophic cardiomyopathy.

Answer 9

signs include bisferiens pulse, S4 or systolic ejection murmur due to obstruction of mitral valve

Question 10

Describe the medical and device therapies for hypertrophic cardiomyopathy.

Answer 10

negative inotropic agents to relieve outflow tract obstruction: Beta blockers, Verapamil, Disopyramide

implantable cardioverter-defibrillator can reduce sudden cardiac death
surgical myomectomy
non-surgical septal reduction

Question 11

This disease occurs with extreme diastolic heart failure, typically resulting from sever ventricular hypertrophy or infiltrative disease (filling pressures are markedly elevated)

Answer 11

restrictive cardiomyopathy