TOPIC15: dilative cardiomyopathy

Question 1

what is cardiomyopathy?

What are the different types?

Answer 1

• intrinsic myocardial dysfunction
• myocardial structural disease with systolic/diastolic dysfunction.
• primary: confined to the myocardium
• secondary:inflammation, immunological, metabolic, genetic (generalized multisystem diseases)
• group of myocardial diseases that are not associated with HTN, congenital heart disease or Coronary artery disease.

1. dilated CMP
2. hypertrophic CMP
3. restrictive CMP
4. arrythmogenic RV dysplasia
5. non- compact cardiomyopathy

Question 2

epidemiology of DCM

Answer 2

epidemiology:

1. cardiac chamber enlargement ( all 4 enlarged) and impaired SYSTOLIC function
2. prevalance is 5-8: 100000
3. 3x more frequent in blacks & males
4. most common non-schemic CMP accounting for 1/3

Question 3

etiology of DCM

Answer 3

1. Idiopathic (most commonly)
2. inherited (25%) -genetic mutation usually AD-
3. myocarditis (usually due to coxsackie A&B)
   
   • lymphocytic infiltrate in the myocardium (chest pain, arrythmias &sudden death) DCM is a late complication i.e if the pts survive the myocarditis.

4.persistent tachycardia (tachymyopathy)

5. metabolic- hemochromatosis, thyrotoxicosis
6. nutritional- vitamin def (thiamine def AKA ‘beri beri heart’)
7. alcohol ‘alcohol cardiomyopathy’
8. drugs (doxorubin)

Question 4

pathomechanism of DCM

Answer 4

Myocardial insult–> remodelling –>thinning of the wall–> spherical enlarged ventricles :

1. ESV, EDV increase
2. EF decreases
3. abnormal propagation of impulses (LBBB, AF, VT)
4. dys-synchronization of mechanical contraction.

Question 5

Diagnosis of DCM

Answer 5

1. History: family & personal
2. Physical examination:
   - decreased BP
   - increased JVP
   - Displaced apical pulse
   - s3 gallop
   - mitral/tricuspid regurgitation
   - crackles (not specific)
   - RHF signs (peripheral edema, ascites, hepatomegaly-right upper quadtrant discomfort, nausea, anorexia-)
   - CCF signs (exertional dyspnea, orthopnea , PND , fatigue)
3. ECG:
   - LVH with pts with chronic LV volume overload
   - Arrythmias eg tacchycardia, AF, ventricular extrasystoles (due to stretching of the conduction system)
   - possible previous MI
   - BBB
   - Poor R-wave progression in anterior leads
4. CXR:
   - cardiomegaly (spherical in shape)
   - possible pulmonary edema (kerley B lines, pleural effusion etc)
5. Echo:
   - GOLD STANDARD for LV dysfunction
   - confirms diagnosis: assesses cardiac walls, EDV, ESV, EF
   - Can show MR, TR or LV mural thrombus
6. exercise testing to assess functional capacity & prognosis
7. Holter monitoring-to assess the presence of prognostically significant ventricular arrythmias
8. cardiac cathetirisation (rarely any indication for this)- ONLY to exclude CAD

Question 6

Treatment of DCM

Answer 6

• Relive symtoms
• improve prognosis
• treat underlying causes

A.Medical:

1. diuretics (loop)
2. ACEi
3. beta blockers
4. aldosterone agonists (omprove sy in pts who continue to be in NYHA class III despite ACEi and beta blockers
5. antiarrythmics
6. anticoagulants (warfarin)
7. digitalis (toxic)
8. vasodilators

B. Surgical:

1. valve replacement
2. revascularization
3. stem cell therapy
4. cardiac transplant

C. Device:

1. CRT( cardiac resynchronization therapy) utilizes biventricular pacing to combat intraventricular and interv dys-synchrony assoc. with ventricular conduction defects.
2. ICD (implantable cardioverter defibrillator) to prevent arrythmias.
3. Pacemaker
4. IABP( intra-aortic balloon pump)
5. BTT ( bridge to transplant theray)
6. DT (destination therapy eg LVAD - mechanical circulatory support)

Question 7

name a variant of DCM

Answer 7

• PERIPARTUM CMP
• symptoms occur in the third trimester
• approx half of the pts will show complete or near-complete resolution over the first 6 months postpartum
• if persistant, worsening and possible death is the outcome.
• cardiac transplantation is indicated.