Cardiomyopathy

Scary thought of the hour– final year exams start tomorrow. That will be me in about exactly 3 years. Time is just going to fly by and I am so not ready to stop being a student and start being a real grown-up.


Cardiomyopathy

Definition: primary disease of the myocardium (heart muscle). Cardiomyopathy may be dilated, hypertrophic or restrictive.

Dilated cardiomyopathy: a dilated flabby heart of unknown cause, which contracts poorly

Hypertrophic cardiomyopathy: HCM is characterised by marked ventricular hypertrophy in the absence of abnormal loading conditions such as hypertension and valvular disease, and left ventricle outflow obstruction from asymmetrical septal hypertrophy. Diastolic filling is impaired and stroke volume is reduced.

Restrictive cardiomyopathy: a rigid myocardium restricts diastolic ventricular filling and the clinical presentation resembles that of constrictive pericarditis

 

Aetiology/ risk factors: the majority are idiopathic

Dilated cardiomyopathy: associated with alcohol, hypertension, haemochromatosis, viral infection, autoimmune, peri/post-partum, thyrotoxicosis, congenital (X-linked), drugs (e.g. doxorubicin, cocaine)

Hypertrophic cardiomyopathy: autosomal dominant inheritance, but 50% are sporadic. 70% have mutations in genes encoding β-myosin, α-tropomyosin, and troponin T (elements of cardiac muscle).

Can present at any age. Family history of sudden death.

Restrictive cardiomyopathy: causes include- idiopathic, amyloidosis, haemochromatosis, sarcoidosis, scleroderma, Löffler’s eosinophilic endocarditis, end myocardial fibrosis.

Epidemiology:

Dilated cardiomyopathy: prevalence = 0.2%

Hypertrophic cardiomyopathy: prevalence = 0.2%

Restrictive cardiomyopathy: rare

Symptoms:

Dilated cardiomyopathy:

-fatigue, dyspnoea

-right ventricular failure- ankle swelling

-atrial fibrillation/ ventricular tachycardia- palpitations

-emboli- e.g. stroke (motor/sensory deficits)

Hypertrophic cardiomyopathy: sudden death may be first manifestation

-angina

-dyspnoea

-syncope

-palpitations (arrhythmias)

-symptoms of congestive cardiac failure

Restrictive cardiomyopathy: features of right ventricular failure predominate

– ankle swelling, abdominal swelling

-fatigue, dyspnoea

-arrhythmias

 

Signs:

Dilated cardiomyopathy:

-pulmonary oedema (bi-basal crackles)

-AF- irregularly irregular pulse

-tachycardia

-hypotension

-raised JVP

displaced, diffuse apex

S3 gallop

-mitral or tricuspid regurgitation (Pan-systolic murmur)

-pleural effusion (stony dull percussion note, reduced breath sounds)

-oedema, ascites

-jaundice, hepatomegaly

Hypertrophic cardiomyopathy: sudden death may be first manifestation

jerky carotid pulse

-a wave in JVP

double apex beat

systolic thrill at lower left sternal edge

-harsh ejection systolic murmur (as with AS, both cause LV outflow obstruction )

-pansystolic murmur of functional mitral regurgitation may also be heard

Restrictive cardiomyopathy: features of RVF

-raised JVP with prominent x and y descents

-hepatomegaly, oedema, ascites

S3 gallop

Kussmaul’s sign (JVP rises with inspiration- also seen in constrictive pericarditis and cardiac tamponade)

 

Investigations:

Bloods-

Dilated cardiomyopathyBNP raised in heart failure, low Na predicts poor prognosis

CXR-

Dilated cardiomyopathy- cardiomegaly, pulmonary oedema

Hypertrophic cardiomyopathy- may show cardiomegaly and signs of heart failure

Restrictive cardiomyopathy- may show cardiomegaly and signs of heart failure

 

Image result for CHEST X RAY CARDIOMYOPATHY

Dilated Cardiomyopathy- showing cardiomegaly

ECG-

Image result for poor r wave progression
Dilated cardiomyopathy-
tachycardia, non-specific T wave changes, poor R wave progression, non-specific ST changes, arrhythmias, conduction defects

Hypertrophic cardiomyopathy- left ventricle hypertrophy, left axis deviation, progressive T wave inversion, deep Q waves (inferior + lateral leads), Atrial Fibrillation, Wolff-Parkinson-White Syndrome, ventricular ectopics, Ventricular Tachycardia (> 3 ectopics occurring together at rate > 120), non-specific ST changes, arrhythmias, conduction defects

 

Image result for hypertrophic cardiomyopathy ecg

ECG of young male with hypertrophic cardiomyopathy showing voltage criteria for LV hypertrophy and repolarisation changes (progressive T wave inversion).

 

Restrictive cardiomyopathy­- low voltage complexes, non-specific ST changes, arrhythmias, conduction defects

 

Image result for Restrictive cardiomyopathy­ ecg

Note the low voltage complexes

 

 

Echo-

 

Dilated cardiomyopathy globally dilated hypokinetic heart and low ejection fraction. Look for mitral and pulmonary regurgitation and left ventricle mural thrombus.

Hypertrophic cardiomyopathy: asymmetrical septal hypertrophy, small left ventricle cavity with hypercontractile posterior wall, dilated left atrium, midsystolic closure of aortic valve, systolic anterior movement of mitral valve

Restrictive cardiomyopathy: non-dilated, non-hypertrophied ventricles; atrial enlargement; preserved systolic function; diastolic dysfunction; granular or ‘sparkling’ appearance of myocardium in amyloidosis.

Also:

Cardiac catheterization– may be necessary for measurement of pressures

Hypertrophic cardiomyopathy- helps assess severity of gradient, coronary artery disease or mitral regurgitation, but may provoke VT.

Restrictive cardiomyopathy- diagnostic (as the ECG, CXR & Echo are often abnormal but non-specific), characteristic pattern of  ventricular pressures change useful in differentiating restrictive cardiomyopathy from constrictive pericarditis

Electrical physiological studies– may be needed e.g. WPW syndrome in Hypertrophic cardiomyopathy.

Exercise test +/- Holter monitor (24h ECG)- e.g. to risk stratify Hypertrophic cardiomyopathy

Endomyocardial biopsy may be helpful in restrictive cardiomyopathy i.e. to identify causes such as infiltrative disease

Genetic analysis rarely necessary

Management:

Dilated cardiomyopathy bed rest, diuretics, digoxin, ACE-inhibitors, anticoagulation, biventricular pacing, ICD (implantable cardioverter defibrillator, for recurrent VTs), cardiac transplantation.

Hypertrophic cardiomyopathy:

beta blocker or verapamil (calcium channel blocker) for symptoms of angina and dyspnoea

-amiodarone for arrhythmia (VT/AF)

-anticoagulate for paroxysmal AF or systemic emboli (warfarin)

-dual chamber pacing used rarely

-septal myomectomy (surgical or chemical- reduces LV outflow tract gradient) in those with severe symptoms

-consider implantable defibrillator (ICD) for individuals at highest risk

-screen family members

Restrictive cardiomyopathy: treat the cause

⇒ Cardiac transplantation may be considered in end-stage heart failure in all cardiomyopathy types

 

Complications: heart failure, arrhythmias (atrial and ventricular)

Dilated cardiomyopathy- mitral and tricuspid regurgitation, AF/VT, heart failure (RVF), thromboembolism, sudden death

Hypertrophic cardiomyopathy- leading cause of sudden cardiac death in the young (due to ventricular tachyarrhythmia), AF/VT, infective endocarditis, thromboembolism, congestive cardiac failure

Restrictive cardiomyopathy: right ventricular failure

Prognosis:

Dilated cardiomyopathy- variable mortality e.g. 40% in 2 years, depends on aetiology

Hypertrophic cardiomyopathy- mortality is 5.9%/yr if < 14yrs and 2.5%/yr if > 14yrs.

Poor prognostic factors = age < 14 yrs, syncope at presentation, FHx of HCM/sudden death

Restrictive cardiomyopathy: poor prognosis, many die within the first year after diagnosis

References: cheese & onion, rapid medicine, Kumar & Clark’s
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s