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Chapter 2: Disorders of pericardium, myocardium and endocardium 71

Aetiology Disorders of the endocardium
Amyloidosis, scleroderma, sarcoidosis, iron storage dis-
eases (haemochromatosis) and eosinophilic heart dis- Infective endocarditis
ease (endomyocardial fibrosis and Loefller’s eosinophilic
Definition
endocarditis).
An infection of the endocardium (endothelial lining of
the heart and valves).
Pathophysiology
Infiltrativediseasecausingadecreaseinventricularcom- Incidence
pliance (increase in stiffness) affecting the myocardium. 6per 100,000 (1500 cases) per year in United Kingdom.
The result is a failure of relaxation during diastole, im-
pairment of ventricular filling and compromise of car- Aetiology
diacoutput.Valvesmayalsobeaffectedbytheunderlying Although infective endocarditis may occur on normal
disease. endocardium, it is more common on a congenital or
acquired cardiac abnormality. Patients most at risk in-
clude those with rheumatic valve disease, mitral valve
Clinical features
prolapse, bicuspid aortic valve, coarctation, ventricular
Patients present in a similar way to constrictive peri-
septal defect or persistent ductus arteriosus. Prosthetic
carditis with a tachycardia, raised JVP with steep x and y
valves may become infected either early (within 60 days
descents. There may be a third heart sound due to abrupt
of implantation) or late.
ventricular filling. Enlarged liver, ascites and peripheral
The clinical pattern is dependent on the infective organ-
oedema may all be seen.
ism:
Streptococcusviridans(α-haemolyticgroupofStrepto-

coccus which includes Streptococcus milleri and Strep-
Complications
tococcus mutans) causes 50% of cases. It is an upper
Thrombus formation is common, and arrhythmias and
respiratory tract commensal.
sudden death occur.
Staphylococcus aureus and Staphylococcus epidermidis

(skin commensals) cause 25% of cases (in acute infec-
Investigations tive endocarditis, Staph. aureus is responsible for 50%
Chest X-ray frequently shows cardiac enlargement, echo of cases).
shows symmetrical myocardial thickening, normal ejec- Enterococcus faecalis causes 10% of cases.
tion fraction but impaired filling. Differentiation from There are many other rarer bacterial causes and fungal
constrictive pericarditis using these methods can be dif- causes include Candida, Aspergillus and Histoplasma.
ficult. Definitive diagnosis may require cardiac catheter- The disease is also dependent on the portal of entry, and
isation and cardiac biopsy. Alternatively amyloid may risk factors include
be diagnosed in other organs or using a serum amyloid Recent dental treatment (even descaling) or poor den-
protein (SAP) scan. tal hygiene.
Infections such as pneumonia, urinary tract infection

or any form of chronic sepsis including skin infection.
Management Carcinoma of the colon (Enterococcus endocarditis).
No specific treatment. Low-dose diuretics and vasodila- Central lines and intravenous drug abuse (tricuspid
tors may provide some relief from symptoms. Patients
valve particularly).
with eosinophilic heart disease may benefit from treat- Post-surgery.
ment with steroids and cytotoxic drugs.
Pathophysiology
Prognosis The clinical picture of infective endocarditis is a balance
The condition is commonly progressive. between the virulence of the organism, the susceptibility