Heart failure Flashcards
What does the term heart failure refer to
The inability of the heart to pump blood strongly enough to meet the body needs
What can heart failure result in
Too little forward flow into the arterial circulation resulting in low blood pressure and poor tissue perforation
What happens to the venous circulation in heart failure
Becomes congested with blood resulting in an increased capillary pressure which forces fluid from the circulation into the tissues
What is oedema
Increase in extravascular fluid
When does heart failure occur in physiological terms
When the heart is unable to pump sufficient blood to supply the body demand
List some of the clinical syndrome of heart failure
Combination of:
1. Breathlessness
2. Oedema
3. Fatigue
List three clinically important considerations we should make in regards to heart failure
- What is the nature of the cardiac malfunction
- What are the boys adaptive mechanism
- What other conditions may be aggravating or precipitating the heart failure
What can heart failure be caused by
Disease of the:
1. Heart muscle (myocardium)
2. The valves
3. Disturbances of the heart rhythm
What is heart muscle dysfunction most commonly due to
Ischemic heart disease or hypertension
What can cause damage to the myocardium
- Drugs and alcohol
- Nutritional deficiencies
- Infections
What is cardiomyopathy
A therm used to cover a group of heart muscle disorders of uncertain cause
What does myocardial disease commonly result in
Left ventricular systolic dysfunction
What is left ventricular systolic dysfunction
Weakness of the left ventricle
What does Weakness of the left ventricle cause
Reduction in ejection fraction
How much blood Is normally ejected from the ventricle with each beat?
More than 60%
What does the term diastolic dysfunction refer to
Poor reaction of the ventricle resulting in impaired fill-in
In whom is diastolic dysfunction more commonly seen
Elderly and hypertensive patients
What happens to the myocardium in myocardial disease
Myocardium is less able to adapt to increasing filling pressures
What is stenosis
Narrowing of a valve
What does valve stenosis result in
Pressure overload of the chamber upstream of that valve
What does aortic stenosis require
An increased left ventricular pressure to eject the blood and the ventricle becomes hypertrophies and can eventually fail
What does mitral stenosis result in
Raised left atrial pressure resulting in dilation of the left atrium
What does calculate regurgitation result in
Volume overload
What can precipitate heart failure
Arrhythmias
What can a severe tachycardia result in
Impairment of cardiac filling during the shortened diastole
What can a severe bradycardia result in
Reduction in the number of contractions to maintain cardiac output
Name the most common chronic arrhythmia
Atrial fibrillation
What are some of the circulatory consequences of heart failure
- Reduced cardiac output
- Increased intracardiac pressure
- Increased back pressure in venous circulation
What can increased back pressure in the venous circulation result in
Increased capillary pressure and leakage of fluid into eh tissues (oedema)
What can result in imbalance of fluids and blood pressure
- Haemorrhage
- Dehydration
- Fluid overload
What does reduced cardiac output result in
Activation of the sympathetic nervous system and the renin–angiotensin– aldosterone system
What does the release of catecholamines adrenaline and noradrenaline stimulates
The force and rate of contraction of the heart
Constricts the blood vessel to maintain blood pressure
What is angiotensin
A vasoconstrictor
What does aldosterone do
Stimulates sodium retention in the kidney and consequently water retention increasing circulatory volume
What can sodium and water retention aggravate
Oedema
What can constant stimulation of the myocardium by catechol- amines result in
Further myocardial damage
Give examples of non cardiac condition that can aggravate heart failure
- Anaemia and hypoxia
- Artery venous shunts
- Hyperthyroidism
- Severe renal failure
- Excessive intravenous fluid therapy
What effect can anaemia and hypoxia have on heart failure
Increases cardiac workload
What effect can Arterio-venous shunts have on heart failure
Require an increased cardiac output
What effect can hyperthyroidism have on heart failure
Causes sympathetic stimulation and concomitant peripheral vasodilation resulting in tachycardia and high cardiac output
What effect can severe renal failure have on heart failure
Impairs excretion of salt and water resulting in fluid overload
What effect can excessive intravenous fluid therapy have on heart failure
Can precipitate pulmonary oedema
What clinical features does left sided heart failure tend to cause
breathlessness due to pulmonary congestion
What clinical features does right sided heart failure tend to cause
Systemic venous congestion with raised beaus pressure and pitting oedema
What is the immediate first aid treatment for a patient with acute pulmonary oedema
- They require hospital admission
- Sit the patient up to optimise both the haemodynamic stress on the heart and the mechanics of breathing.
- Oxygen should be given, and patients with ischaemic heart disease should take their GTN
Give examples of some drugs used to manage heart failure
- ACE inhibitors
- Angiotensin
- spironolactone in low doses
- Beta blockers
- Diuretics
- Vasodilators
- Digoxin
- Phosphodiesterase inhibitors
What can ACE inhibitors do
Reduce mortality by 25% at all levels of severity
What can ACE inhibitors cause
Renal impairment and hyperkalaemia
What do spironolactone do
Reduce mortality in severe heart failure patients that are already being treated with ACE inhibitors
Give examples of Phosphodiesterase inhibitors
enoximone and milrinone.
What can inhibition Phosphodiesterase cause
ntracellular accumulation of cAMP, which results in a rise in calcium entry. This increases the force of myocardial contraction.
Which drugs should we be careful about giving to patients with heart failure and why
NSAIDs as they may cause fluid retention and acute renal failure in patients already taking diuretics and ACE inhibitors
