Heart failure affects 10% of people above 65 years of age, and more than 50% of those above 85 years. The National Heart Foundation defines chronic heart failure as:

“A complex clinical syndrome that is frequently, but not exclusively, characterized by an underlying structural abnormality or cardiac dysfunction that impairs the ability of the left ventricle (LV) to fill with or eject blood, particularly during physical activity.”

Normal myocardium function involves organised depolarisation of muscle fibre, muscle contraction (systole), muscle relaxation (diastole), normal filling of the heart before contraction, and normal flow of blood out of the heart after contraction.

Description

Heart failure often starts after an event, such as a myocardial infarction, leading to a decline in the pumping capacity of the heart. In the short term, compensatory mechanisms are activated, returning cardiac output to normal. Such adaptive mechanisms include the adrenergic nervous system, renin-angiotensin-aldosterone system, and cytokine system.

Over long periods these compensatory mechanisms lead to adverse remodelling of the heart and reduce the pumping capacity. Asymptomatic heart failure gradually progresses to symptomatic heart failure.

Chronic heart failure symptoms can occur at rest or during physical activity. The New York Heart Association classifies the stages of heart failure, based on clinical symptoms, as follows:

Class I No symptoms during any activity
Class II Slight limitation of physical activity. Ordinary physical activity results
in fatigue, palpitation, dyspnoea or angina pectoris
(mild chronic heart failure)
Class III Marked limitation of physical activity. Less than ordinary physical activity leads to symptoms (moderate chronic heart failure)
Class IV Unable to carry on any physical activity without discomfort.
Symptoms of chronic heart failure present at rest
(severe chronic heart failure)

Causes

Systolic heart failure has a low left ventricular ejection fraction (usually less than 40%) due to reduced contractility and an enlarged left ventricle. It is often associated with coronary artery disease, idiopathic dilated cardiomyopathy, hypertension, and aortic stenosis. Symptoms include fatigue. Loss of lean muscle mass, dyspnoea, impaired renal function, and altered mental status.

The National Heart Foundation defines diastolic heart failure (also known as heart failure with preserved systolic function) as “the impaired filling of the left ventricle of the heart in response to a volume load, despite normal ventricular contraction.” This is often caused by reduced ventricular relaxation and/or increased ventricular stiffness. Diastolic heart failure is usually diagnosed by exclusion of systolic heart failure, i.e. where a patient presents with the clinical characteristics of heart failure although systolic function is normal on an echocardiogram. Systolic and diastolic heart failure can occur together.

Consequences

The left ventricle pumps blood around the body and, when it fails, it enlarges but reduces the volume of blood pumped. This can lead to blood backing up into the left atrium and also the lungs. Symptoms of left ventricular heart failure include shortness of breath and orthopnoea (patient needs to sit or stand to breath normally).

The right ventricle pumps blood to the lungs and, when it fails, blood backs up into the right atrium and systemic circulation. The results are peripheral oedema (swelling of the legs and ankles) and other symptoms including hepatic congestion, raised jugular venous pressure, and ascites.

As the heart fails, the lack of perfusion of body organs can cause patients to become fatigued, and lack of cerebral blood flow can cause confusion and drowsiness. Raised jugular venous pressure causes distension of neck veins. Swollen ankles and legs are worse at the end of the day. Increased pressure in systemic veins can lead to bowel oedema (haemorrhoids) and/or ascites.

The measurable signs of heart failure, along with the symptoms which the patient may describe are summarised in Table 1.

Table 1. Signs and Symptoms of Heart Failure.

Signs Symptoms
Breathlessness
Wheeze
Tachycardia
Ascites
Tender large liver
Third or fourth heart sound
Raised jugular venous pressure
Basal crackles
Wheezing
Ankle oedema
Cardiomegaly
Murmurs
Swollen ankles
Cough at night
Fatigue
Need to sit out of bed
Need to open windows for air
Wheezing
Painful and/or swollen abdomen

References:

  1. National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand. Quick reference guide. Diagnosis and management of chronic heart failure.
    Updated October 2011.
  2. Jackson S, Peterson G. Essential CPE: Heart Failure. Canberra: Pharmaceutical
    Society of Australia; December 2010.

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