4- Dilated cardiomyopathy.

What is the definition of cardiomyopathy

myocardial disorder in which the heart muscle is structurally and functionally abnormal

In the absence of what diseases can you CM be diagnosed

• coronary artery disease

• hypertension

• valvular disease

• congenital heart disease

• or the degree is not sufficient to cause the observed myocardial abnormality

What is the classification of cardiomyopathies- ESC guidelines

• hypertrophic

• dilatative

• non dilated left ventricular

• arrhythmogenic

• restrictive

• un classified- non compaction, Tako-Tsubo

What are secondary causes of DCM

• myocarditis

• chronic alcohol disease

• endocrine disorders

• chronic tachyarrhythmia

What is DCM

• characterised by cavity enlargement and impaired systolic function

What is the etiology of DCM

• familial 30-40%- most commonly AD

• idiopathic

• secondary causes

  • infections- Coxsackie B virus myocarditis

  • chronic alcohol disease

  • endocrine disorders- eg hyperthyroidism

  • chronic tachycardia- eg A fib

What is the morphology of DCM

• Reversible/ irreversible damage of the myocardium

• increased interstitial fibrosis

• decreased systolic function

• dilated cavities

• thin ventricular walls

What are the symptoms of DMC

• progressive disease- asymptomatic in early stage

• symptoms of HF- fatigue

• progresses- all signs of L and R ventricular HF

What is the pathomechanism of DCM

1. Causative factors decrease the contractility of myocardium

2. compensatory Frank Starling law- to maintain CO

3. increased EDV- preload

4. myocardial remodeling

5. eccentric hypertrophy + dilation of ventricle

6. decreased myocardial contractility

7. systolic dysfunction and decreased EF → HF

• decreased LV contractility due to dilation → LSHF then eventual RSHF

What do you do to diagnose DMC

• ECG

• Imaging- echo, CMR, coronary CT angiography

What is seen during a physical examination

• decreased BP, increased JVP, narrow PP

• possible signs of RSHF- peripheral oedema, ascites, hepatomegaly

• displaced apex, murmurs

What are the signs of DMC on an ECG

• conduction disturbances- LBBB

• atrial fibrillation

• ventricular arrhythmias

What is seen on an echo, CMR

• Echo is GOLD STANDARD

• dilated cavities

• diffuse hypokinesis

• functional mitral/ tricuspid regurgitation

What are the complications of DCM

• arrhythmias-

  • incl A fib, malignant arrhythmias- v. tachycardia, v. fibrillation

• progression of systolic and diastolic dysfunction

• functional mitral/ tricuspid regurgitation

• intracardiac thrombus- LV, LA appendage

• progression of HF, decompensation

How do you treat the underlying causes of DCM

• avoid cardiotoxic agents, abstain from alcohol

• treat infection and endocrine disorders

What is the treatment of HF

• ACEi, BB, diuretics, digoxin, aldosterone antagonists

• anticoagulants

What is the surgical treatments for DCM

• if LVEF <35% → ICD to prevent SCD caused by V fib

• heart transplant

How do you prevent SCD

• ICD is recommended

When do you do primary prevention

• symptomatic HF and EF <35% after ≥3 months OMT

When do you do secondary prevention

• haemodynamically not tolerated VT/VF without any reversible cause

What are the non dilated left ventricular cardiomyopathies

• isolated left ventricular dysfunction

• non ischemic left ventricular scar

• fatty infiltration

• left ventricular wall motion abnormalitie