Heart Failure Flashcards
What is heart failure defined as?
A state in which the heart fails to maintain an adequate circulation for the needs of the body despite an adequate filling pressure
What is the primary cause of systolic heart failure?
Ischaemic heart disease
Other than IHD, what are the causes of HF?
Hypertension Dilated cardiomyopathy Valvular heart disease Restrictive cardiomyopathy Hypertrophic cardiomyopathy Pericardial disease High-output heart failure Arrythmia
What can cause dilated cardiomyopathy?
Bugs Alcohol Drugs Poisioning Pregnancy
What can cause restrictive cardiomyopathy?
Amyloidosis
What does the force developed in the myocardium depend on?
The degree to which the fibres are stretched (or how much the heart is filled)
What happens to the force developed in the myocardium in heart failure?
The heart can no longer produce the same amount of force (or cardiac output) for a given level of filling
What will be seen on the Starlings Law of the Heart Curve with heart failure?
In mild failure, will be less cardiac output for the same filling
In gross failure, after a point, increasing filling will result in reduced cardiac output
What are the types of heart failure?
Class I
Class II
Class III
Class IV
What will be seen in class I heart failure?
No symptomatic limitation of physical activity
What will be seen in class II heart failure?
Slight limitation of physical activity
Ordinary physical activity results in symptoms
No symptoms at rest
What will be seen in class III heart failure?
Marked limitation of physical activity
Less than ordinary physical activity results in symptoms
No symptoms at rest
What will be seen in class IV heart failure?
Inability to carry out physical activity without symptoms
May have symptoms at rest
Discomfort increases with any degree of physical activity
Does heart failure affect one or both sides of the heart?
Can be either
Does right-sided heart failure occur on its own?
Rarely
When may right sided heart failure occur on its own?
In the case of chronic lung disease
What is the most common scenario in heart failure?
Left-sided heart failure that raises pulmonary arterial pressure, leading to additional right sided heart failure
What is it called when both ventricles are affected in heart failure?
Congestive heart failure
What is heart failure often divided to in clinical practice?
Left sided heart failure Right sided heart failure Biventricular (congestive) heart failure Systolic heart failure Diastolic heart failure
What are the symptoms of left sided heart failure?
Fatigue, shortness of breath upon exertion or when lying lat, waking from sleep with shortness of breath
Tachycardia
Cardiomegaly
3rd or 4th heart sound
Functional murmur of mitral regurgitation
Basal pulmonary crackles
Peripheral oedema
What is cardiomegaly?
Displaced apex beat
What is it called when there is a 3rd or 4th heart sound?
Gallop rhythm
When is right sided heart failure most common?
Secondary to left heart failure
What can cause right sided heart failure?
Chronic lung disease Pulmonary embolism/hypertension Pulmonary/tricuspid valvular disease Left to right shunts (ASD/VSD) Isolated right ventricular cardiomyopathy
What are the symptoms of right sided heart failure?
Distension and fluid accumulation (peripheral oedema) in areas drained by systemic veins Fatigue Dyspnoea Anorexia Nausea Raised JVP Tendor, smooth hepatic enlargement Dependent pitting oedema Ascities Pleural effusion
What is activated in heart failure?
The renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system
Why are the sympathetic nervous system and RAAS activated in heart failure?
In an attempt to maintain cardiac output
What effect does the activation of the sympathetic nervous system and RAAS have?
Making an already struggling heart work harder
What does a drop in blood pressure, such as in heart failure, stimulate?
Renin release from the kidneys
What is renin?
An enzyme which catalyses the conversion of angiotensin to angiotensin I
What happens to angiotensin I?
It is converted to angiotensin II by ACE
What is angiotensin II?
A strong vasoconstrictor
What does angiotensin II promote?
Release of aldosterone from the kidneys
What does aldosterone cause?
Salt and water retention in the kidneys, increasing blood volume
What does the sympathetic nervous system cause when theres a drop in blood pressure?
Causes vasoconstriction of the blood vessels via the alpha 1 receptor, increasing blood pressure
What is the result of SNS induced increased blood pressure in heart failure?
It increases the workload on the heart by increasing both the preload and the afterload
What will sympathetic innervation of the hearts ß1 receptors cause?
An increase in both chronotropy and inotropy
What drugs are used in the treatment of heart failure?
ACE-inhibitors Diuretics ß-blockers Ca channel blockers Organic nitrates Cardiac glycosides
Why are ACE-inhibitors used in the treatment of heart failure?
To prevent the conversion of angiotensin I to II, and thus have an indirect vasodilatory and diuretic effect, both of which are beneficial in the treatment of heart failure by reducing the workload of the heart
Why are diuretics used in the treatment of heart failure?
Reduce blood volume and thus oedema
What are ß-blockers used to do?
Prevent sympathetic innervation of the myocardium in an attempt to reduce the hearts work load
What are the principles of the management of heart failure?
Correct underlying cause
pharmacological measures first, then pharmacological therapy.
Treat complications/associated conditions/cvs risk factors
What is the purpose of pharmacological therapy in the management of heart failure?
Symptomatic improvement
Delay of progression of heart failure
Reduce mortality
What is the purpose of Ca channel blockers in the treatment of heart failure?
Reduce contractility of the myocardium
What is the purpose of organic nitrates in the treatment of heart failure?
Veno/vasofilator, resulting in a reduction in BP
What is the purpose of cardiac glycosides in the treatment of heart failure?
Increase CO and heart contractility by inhibiting the Na/K pump
Raising intracellular Na inhibits NCX, so intracellular Ca increases, and so increase in contractility
