Heart failure Flashcards
What is heart failure?
Heart failure is an abnormality of the cardiac structure or function resulting in the inability of the heart to supply adequate blood supply and oxygen delivery to peripheral tissues and organs
What are the common causes of heart failure?
Coronary artery Disease Chronic Hypertension Myocardial infarction valve disease Cardiomyopathy Myocarditis Arrhythmias
What haemodynamic changes occur in heart failure?
Decrease in stroke volume and cardiac output
Decreased arterial pressure
Increased venous pressure and preload
Left ventricular hypertrophy and dilation
Increased blood volume
What compensatory mechanisms does the body use to maintain cardiac output?
Left ventricular hypertrophy: thickening of the myocardium to allow greater cardiac contraction and cardiac output.
Renin-angiotensin-aldosterone system: increases sympathetic activity, arteriole vasoconstriction, increased renal reabsorption which increases blood volume. Release of aldosterone and ADH to increase water reabsorption. This increases blood volume and preload.
By the Frank Starling Mechanism, this increases cardiac output.
Activation of the sympathetic nervous system:
increases heart activity to increase stroke volume and CO
Increases vasoconstriction of arteries and veins
How do these compensatory mechanisms actually end up not being effective?
Hypertrophy makes the blood vessel chamber so less blood can fill it. Also, increased contraction enquires a greater blood supply which the heart cannot provide.
Increased fluid retention also causes pulmonary and peripheral oedema. The increased stretch of the heart caused by preload also requires a greater blood supply to heart which it cannot provide.
This creates the symptoms of fatigue, swelling and breathlessness.
What drug treatment Is recommended for those with heart failure?
Beat blockers Angiotensin receptor Blockers ACE inhibitors Diuretics Mineralcorticoid Aldosterone receptor antagonists Digoxin Inotropes
What alternative options are available for those with heart failure?
Implantable Cardioverter Defibrillator
Left ventricular Assist device
Heart transplant
