Dilated Cardiomyopathy

Question 1

What is it by definition?

Answer 1

Left or biventricular dilation with structural and/or functional systolic dysfunction in the absence of CAD, abnormal loading pressures or Congenital heart disease

Question 2

What is the most common cardiomyopathy?

Answer 2

Dilated cardiomyopathy (DCM)

Question 3

What is eccentric LVH?
- what happens to the myocardium?
- what happens to the ventricles
-what happens to the sarcomeres?

Answer 3

Myocardial thinning
Ventricular enlargement
Duplication of sarcomeres in series (lengthening)

Question 4

What is concentric LVH?
-what happens to the myocardium, ventricles, and sarcomeres?

Answer 4

Myocardial thickening
Ventricular diminution
Duplication of sarcomeres in parallel

Question 5

Decreased LV contractility due to dilation leads to?

Answer 5

Left sided HF and eventually right sided

Question 6

Clinical features of DCM?

Answer 6

Gradual development of CHF
-dyspnea
-edema
-angina
-fatigue

Question 7

Clinical features: physical examination of DCM

Answer 7

Systolic murmur secondary to mitral or tricuspal valve regurgitation
-S3 gallop
- JVD
- bilateral tales
- peripheral edema
- ascites

Question 8

Diagnostics of DCM include what tests?

Answer 8

Echo and CXR

Question 9

Etiology bold text

Primary causes:
Secondary: (ABCCCDD)

Answer 9

Primary: Idiopathic or genetic mutation in the TTN gene (encodes for intrasarcomeric protein titin (connectin) and the MYH7 gene (encodes the beta-myosin heavy chain)
Secondary: Alcohol use, Beriberi, cocaine, Coxsackie B Virus, Chagas, Doxorubicin/Daunorubicin

Question 10

What is the pathophysiological pathway of DCM?
(Long one)

Answer 10

Causative factors decrease contractility of the myocardium —> Activation of compensatory mechanisms (Frank-Starling Law) to maintain cardiac output —> Causing increased end-diastolic volume (preload) —> myocardial remodeling —> eccentric hypertrophy —> reduced myocardial contractility —> system dysfunction and reduced ejection fraction —> heart failure

Question 11

Treatment of DCM:
Overview only
(Specificity will be in other cards)

Answer 11

Treat underlying cause of DCM
avoid cardiotoxic agents, if possible
Treat CHF
In severe or refractory disease: consider implanted cardioverter, LV assist devices, or heart transplant

Question 12

Managing underlying etiology:
Such as what disorders?

Answer 12

Substance use, endocrine disorders, infections, chemotherapy-related cardiomyopathy, peripartum cardiomyopathy, autoimmune diseases

Question 13

Management of substance abuse disorders consist of?

Answer 13

Encouraging complete abstinence from the causative substance

Question 14

Which endocrine disorders and what is their treatment?

Answer 14

1. Hyperthyroidism: start B-Blockers (aim to normalize HR)
2. Hypothyroidism: Start levothyroxine replacement
   
   • in older patients, start thyroid hormone replacement at 25-50% of the expected required dose
3. Acromegaly: Start somatostatin analogues or refer for surgery

Question 15

What infections are managed and what’s the treatment?

Answer 15

1. Myocarditis: management of myocarditis
   
   • pt’s with giant cell myocarditis: start immunosuppressants
2. HIV: start antiretroviral therapy
3. Chagas’ disease: give antitrypanosomal therapy (e.g., benznidazole, nifurtimox)