Cardiomyopathy

Question 1

What is cardiomyopathy?

Answer 1

Cardiomyopathy refers to a collection of disease processes affecting the heart muscle that cause impaired pumping of the involved muscle. There are 3 main types:

Dilated cardiomyopathy - Most common type of cardiomyopathy. Caused by dilation of the ventricles (Just left or Both)

Hypertrophic cardiomyopathy – Left sided ventricular hypertrophy, leading to left ventricular outflow obstruction. It is autosomal dominant

Restrictive cardiomyopathy – The heart muscle becomes rigid (but not dilated or hypertrophied like in the above conditions) causing impaired diastolic filling

Question 2

What are the causes of cardiomyopathy?

Answer 2

Dilated cardiomyopathy – Myocardial Ischaemia, Alcoholic, Hypertension, Hyperthyroidism, Idiopathic

Hypertrophic cardiomyopathy – Congenital (Autosomal Dominant), Hypertension

Restrictive cardiomyopathy - Idiopathic, Sarcoidosis, Amyloidosis, TB, Haemochromatosis

Question 3

What will you find on a history taking of cardiomyopathy?

Answer 3

Symptoms:
Dilated cardiomyopathy – Congestive Heart Failure (Left side worst affected), AF, Ventricular tachycardia
Hypertrophic cardiomyopathy - Congestive Heart Failure, Chest Pain, Palpitations, Syncope, SOB, Sudden death/Ventricular Fibrillation (commonly in young athletes)
Restrictive cardiomyopathy - Congestive Heart Failure (Right side worst affected), AF, Ventricular tachycardia

Specific Questions to ask:
Family history of sudden cardiac death -Think hypertrophic cardiomyopathy

Question 4

What will you find on examination of a patient with cardiomyopathy?

Answer 4

Dilated Cardiomyopathy – Tachycardia, Hypotension, Raised JVP, Displaced/Diffuse apex beat, S3 Gallop Rhythm, Signs of heart failure

Hypertrophic cardiomyopathy – Jerky Pulse, Double apex beat, S4 heart sound, Alpha wave in JVP, Systolic thrill at lower left sternal edge and ejection systolic murmur, LVH

Restrictive Cardiomyopathy - Kussmaul’s/Pulsus paradoxes, S3 and S4 heart sounds, non-palpable apex beat, Prominent X/Y descent in JVP, Signs of heart failure

Question 5

What investigations will you order in cardiomyopathy?

Answer 5

Bedside:
ECG:
Dilated Cardiomyopathy – T wave changes (nonspecific) and poor R wave progression
Hypertrophic cardiomyopathy - LVH (Tall QRS V5/6), Progressive T wave inversion, Pathological Q wave in inferior and lateral leads, Arrhythmias (AF, WPW, VT, VF)

Bloods:
FBC – Looking for infection/Precipitating anaemia
U&E – Dilated cardiomyopathy associated with hyponatraemia
LFTs – Congestive heart failure can affect the liver
Troponin – Rule out MI as cause of chest pain
TFT – Thyrotoxicosis is a cause of dilated cardiomyopathy
BNP – Assess ventricular involvement

Imaging:
CXR – Cardiomegaly and signs of heart failure
Echocardiogram – Diagnostic test

Special Tests:
Transthoracic Doppler Echocardiography
Dilated Cardiomyopathy – Globally dilated hypokinetic heart muscle with poor ejection fracture
Hypertrophic cardiomyopathy – Asymmetrical septal hypertrophy
ECG stress test to rule out ischaemic heart disease that may be predisposing
Cardiac catheterisation - help in excluding coronary artery disease as a cause

Question 6

What is the treatment of cardiomyopathy?

Answer 6

Dilated Cardiomyopathy –Treat as heart failure (Diuretic’s, Ace inhibitors, Beta blockers) and Anticoagulation (Prone to AF)

Hypertrophic Cardiomyopathy – Calcium channel/Beta blocker to reduce contractility, Anticoagulation, Implantable cardiac defib. If medical management not working consider surgical myectomy

Restrictive Cardiomyopathy – Treat the underlying cause and symptomatic management
Refer end stage patients for heart transplant