dilated cardiomyopathy

Question 1

basics

Answer 1

Dilated cardiomyopathy (DCM) basics

• dilated heart leading to systolic (+/- diastolic) dysfunction
• all 4 chambers affected but LV more so than RV
• features include arrhythmias, emboli, mitral regurgitation
• absence of congenital, valvular or ischaemic heart disease

Question 2

causes

Answer 2

Causes often considered separate entities

• alcohol: may improve with thiamine
• postpartum
• hypertension

Other causes

• inherited (see below)
• infections e.g. Coxsackie B, HIV, diphtheria, parasitic
• endocrine e.g. Hyperthyroidism
• infiltrative* e.g. Haemochromatosis, sarcoidosis
• neuromuscular e.g. Duchenne muscular dystrophy
• nutritional e.g. Kwashiorkor, pellagra, thiamine/selenium deficiency
• drugs e.g. Doxorubicin

Inherited dilated cardiomyopathy

• around a third of patients with DCM are thought to have a genetic predisposition
• a large number of heterogeneous defects have been identified
• the majority of defects are inherited in an autosomal dominant fashion although other patterns of inheritance are seen

Question 3

define

Answer 3

= dilated, flabby heart of unknown cause

Question 4

s/s

Answer 4

Clinical features:

• congestive heart failure
• thrombo-embolism
• arrhythmias e.g. atrial fibrillation, especially if alcohol is a causative factor
• apex beat is displaced and diffuse
• soft S1 (possible mitral or tricuspid incompetence)
• loud P2 if pulmonary hypertension secondary to left ventricular failure
• gallup rhythm - S3 (left ventricular and right ventricular failure)

Question 5

ix

Answer 5

• Investigation to exclude treatable or reversible causes of heart failure, particularly coronary artery disease, valvular heart disease, hypothyroidism, thyrotoxicosis, haematochromatosis, collagen vascular disorders, and alcohol or drug related heart muscle disease.
• Chest radiology reveals moderate to marked cardiac enlargement with pulmonary venous hypertension.
• ECG demonstrates diffuse nonspecific ST-T wave abnormalities.
• Echocardiography shows left ventricular dilatation and dysfunction.
• Radionuclide studies show left ventricular dilatation and dysfunction.
• Cardiac catheterization reveals left ventricular dilatation and dysfunction; elevated left and often right sided filling pressures; diminished cardiac output.

Question 6

mx

Answer 6

Patients should be advised to stop drinking because of:

• depressant effects of alcohol on heart muscle
• difficulty in diagnosing alcohol-induced cardiomyopathy

Treatment of cardiac failure:

• treatment with angiotensin converting enzyme (ACE) inhibitors and beta blockers in line with management of chronic cardiac failure
• diuretics for management of symptoms with congestion; digoxin may also be required

Anti-arrhythmic drugs:

• only necessary if symptomatic arrhythmias or ventricular ectopics are so frequent as to impair cardiac output
• amiodarone is the agent of choice

Anticoagulation:

• long-term anticoagulation is the rule rather than the exception for most patients
• is mandatory if there is co-existent atrial fibrillation

Other treatment options include cardiac transplantation and cardiomyoplasty.

Question 7

prog

Answer 7

• This is dependent on the severity of myocardial dysfunction.
• It is poor when there is a short history with severe dilatation and poor functioning left ventricles, and there is no sustained response to treatment. If, in addition, right sided heart failure, mitral regurgitation, and atrial fibrillation are present, the prognosis is particularly bleak. End-stage heart failure may occur within weeks rather than months.
• Ventricular ectopics are an indicator of poor prognosis as they mainly occur in patients with the most diseased ventricles.
• Progression from mild disease to severe disease is not inevitable.
• About 50% of deaths occur suddenly e.g. from arrhythmias.
• The prognosis of alcohol induced cardiomyopathy is related to the degree of alcohol consumption