The Cardiovascular System|
Synonyms : Cardiac Failure, Cardiac Insufficiency, Congestive Heart Disease - CHD, Congestive Heart Failure - CHF, Heart Failure, Myocardial Insufficiency
failure is an imprecise term used to describe the state that develops when the
heart cannot maintain an adequate cardiac output. In the mildest forms of
heart failure cardiac output is adequate at rest and becomes inadequate only
when the metabolic demand increases during exercise or some other form of
stress. Almost all forms of heart disease may lead to heart failure and it is
important to appreciate that the term refers to a clinical syndrome rather than a specific diagnosis.
Types of Heart Failure
1. Acute and chronic heart
failure may develop suddenly, as in
myocardial infarction, or gradually,
as in progressive valvular heart disease or prolonged hypertension.
there is gradual impairment of cardiac function a variety of compensatory
changes may improve overall cardiac function (activation of the sympathetic
nervous system, myocardial hypertrophy, chamber enlargement, activation of the
renin-angiotensin-aldosterone system, release of antidiuretic hormone). These
mechanisms aim to increase cardiac output either by directly increasing
cardiac contractility/heart rate or increasing blood volume and venous return,
which then stimulate pumping activity of the heart.
long as these compensatory mechanisms manage to maintain normal or near normal
cardiac output, the patient is said to have compensated
heart failure, which is generally asymptomatic. However a minor
event such as an intercurrent infection, physical or emotional stress,
inappropriate reduction of therapy or pregnancy, may precipitate overt (symtomatic)
decompensated heart failure
in this type of patient. Decompensated heart failure eventually develops in
most patients when the weakened heart can no longer respond to constant
2. Left, right and
biventricular heart failure
left side of the heart is a term for the functional unit of the left atrium
and left ventricle together with the mitral and aortic valves, and the right
side stands for the right atrium, right ventricle, tricuspid and pulmonary
Left-sided heart failure is a reduction in the left
ventricular output with consequent increase in the left atrial and pulmonary
venous pressure. An acute increase in left atrial pressure may cause pulmonary
congestion or pulmonary oedema, but a more gradual increase in the left atrial
pressure often leads to reflex pulmonary vasoconstriction which protects the
patient from pulmonary oedema at the cost of pulmonary hypertension and right
heart failure is a reduction in right ventricular output with subsequent blood
stasis in peripheral tissues. Isolated right heart failure may develop as a
result of chronic lung disease such as chronic bronchitis and emphysema (so
called cor pulmonale). In emphysema there is widespread destruction of
alveolar walls leading to reduction in pulmonary vascular bed (pulmonary
‘pipeline?, and increased resistance to blood flow. In chronic bronchitis
due to irreversible airway obstruction there is widespread hypoventilation of
many areas in the lungs, which in turn leads to cutting off blood flow through
them as an autoregulatory mechanism (gas exchange can not occur in these
Biventricular heart failure is a failure of both sides of the heart developing because the disease process such as cardiomyopathy (progressive weakening of the heart usually of unknown cause) or ischaemic heart disease, affects both ventricles, or because disease of the left heart leads to chronic elevation of the left atrial pressure, pulmonary hypertension and subsequent right heart failure.
failure can develop in following circumstances:
(pressure overload) is found in systemic or pulmonary hypertension and aortic
or pulmonary valve stenosis. Initial heart response is hypertrophy (increased
muscle mass) to accommodate increased work in maintaining normal cardiac
output. At some point this compensatory mechanism will no longer suffice and
overt heart failure will follow.
is observed in mitral or tricuspid valve stenosis or more rarely in
constrictive pericarditis that results in formation of firm, inelastic
connective tissue layer that covers the heart and restricts its expansion.
More acute type of ventricular inflow obstruction is cardiac tamponade after
ventricular wall rupture in extensive myocardial infarction.
occurs in intracardial shunting of blood (e.g., septal defects ?
‘holes? which can be inborn or acquired as a result of myocardial
infarction) or in valvular incompetence with backflow of blood (e.g., mitral
or aortic incompetence will eventually lead to left heart failure)
4. Impaired ventricular function (reduced cardiac contractility) can be a consequence of diffuse myocardial diseases such as myocarditis and cardiomyopathy or localised myocardial disease such as myocardial infarction (reduced cardiac contractility or grave cardiac arrhythmia such as ventricular fibrillation).
Clinical features: < BACK TO TOP >
clinical picture depends on the nature of the underlying heart disease, the
type of heart failure that it has produced and the compensatory mechanisms
that have developed.
Low cardiac output causes fatigue, tiredness and poor effort tolerance, pale skin, cold
peripheries, low blood pressure, oliguria (reduced volume of urine).
Left heart failure may cause breathlessness, orthopnoea and paroxysmal nocturnal dyspnoea
with late inspiratory crackles over the lung bases (heard on auscultation),
cough with pink-tinged or brownish sputum due to presence of traces of blood
or ‘heart failure?cells (macrophages filled with haemosiderin)
respectively; these features are absent if there is marked pulmonary
vasoconstriction. In acute pulmonary oedema the patient presents with extreme
dyspnoea, tachypnoea, cyanosis, restlessness and anxiety with a sense of
Right heart failure produces hepatic congestion (moderately enlarged tender liver), peripheral oedema and ascites or pleural effusion (hydrothorax) due to accumulation of fluid. Distribution of peripheral oedema is influenced by gravity and it affects more lower parts of the body (so called dependant oedema). This means that in mobile patients the oedema affects the ankles and shins, whereas in bedbound patients it collects around the sacrum.
Diagnosis: < BACK TO TOP >
findings and physical examination are very indicative.
shows signs of compensatory heart changes (myocardial hypertrophy, increased
heart rate) and sometimes arrhythmias as a complication of the heart failure.
X-ray is done to detect changes in the heart and lung (cardiac enlargement,
pulmonary congestion and oedema).
Echocardiography is extremely valuable and may demonstrate the underlying problem (e.g., valve abnormalities) or the current status of the heart vitality (e.g., weak contractions, reduced stroke volume, increased end-systolic volume).
Management < BACK TO TOP >
heart failure is not a disease, management should be directed to the
underlying condition (e.g., replacement of damaged valves).
rest is helpful (bed-rest increases renal blood flow and will often initiate
diuresis without any adjustment in diuretic therapy).
are usually the first line of treatment, leading to a reduction in blood and
plasma volume, and may also cause a small but significant degree of arterial
and venous dilation.
converting enzyme (ACE) inhibitors (listed earlier) act to prevent the
conversion of angiotensin I to angiotensin II, thereby counteracting salt and
water retention, peripheral arterial and venous vasoconstriction. A
combination of a diuretic and an ACE inhibitor is a preferred option.
II antagonists (listed earlier) block the action of angiotensin II and have
similar effects to ACE inhibitors, but with the advantage of not causing dry
cough as a side effect.
glycosides (digoxin [Lanoxin]) may be effective in few selected cases of
severe heart failure that has not responded to treatment with a diuretic and
an ACE inhibitor.
Heart failure carries a poor prognosis. Although the outlook depends, to some extent, on the underlying cause of the problem, approximately 50% of patients with severe heart failure will die within two years. Many patients die suddenly, often due to malignant ventricular arrhythmias such as ventricular tachycardia and fibrillation, or myocardial infarction. Others may eventually die from pulmonary oedema/respiratory failure, sometimes with superimposed episode of pneumonia.
Prognosis < BACK TO TOP >
Nutrition < BACK TO TOP >
Nutrition that alleviate or prevent Cardiac Failure :-
Herbs < BACK TO TOP >
Herbs that alleviate or prevent Cardiac Failure :-
(source : -)
3 5 June 20096December 2005
10 December 2004 Human Rights DayInternational Day of Disabled Persons
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speaker Mr NgThian Watt the Principal Trainer from
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