Heart Failre As A Drug Target Flashcards
Heart failure define
Inability of the heart to pump blood effectively around the body
Heart failure is not?
Heart attack : myocardial infarction
Heart stopping : cardiac arrest
Sign of imminent death
Cause of heart failure
Ischaemic heart disease
Hypertension
Valve disease
Cardiomyopathy- disease of the muscles of the heart
Arrhythmias - problems of heart rhythm
Right sided heart failure
Fluid build up (oedema ) in body, typically legs : peripheral oedema, which may be pitting
Left sided heart failure
Fluid build up (oedema) in lungs -pulmonary oedema
Symptoms of right sided heart failure
Heavy painful legs
Difficulty walking
Skin infection
Tiredness, light headedness,fainting
Symptoms of left sided heart failure
Breathlessness , especially on exertion or lying flat
Cough with pink sputum
Tiredness, light headedness,fainting
Congestive cardiac failure
Failure of both sides of the heart
Measurement of heart failure: most important investigation
Brain natriuretic peptide (BNP) -correlated with increased ventricular blood volume
Echocardiogram function: ejection fraction - how much blood from ventricle pumped out?
Normal ejection fraction is?
50-70%
Brain natriuretic peptide (BNP) is?
Hormone secreted by cardiomyocytes in ventricles in response to stretching
Types of heart failure by ejection fraction
Heart failure with reduced ejection fraction -less blood pumped out
Heart failure with preserved ejection fraction -stiff heart muscle can’t relax normally
Preload define
The amount of stretch on cardiac muscle after diastole i.e the amount of blood in the ventricle
How to reduce preload :
Loop diuretics (eg furosemide)
Act on Na+ K+ 2CL- symporter in thick ascending limb of LOH
Aldosterone antagonist (spironolactone) decrease sodium reabsorption
After load:
The amount of pressured the heart has to pump against i,e blood pressure in aorta
How to reduce after load?
Anti hypertensives: ACE inhibitors (Ramipril), Calcium channel blockers (Amlodipine )
Rate control
Slowing : slowing heart down improves ejection fraction
How to reduce heart?
B1-selected adrenergic receptor antagonists (aka beta blockers e.g bisoprolol
Improves mortality but, can make symptoms of heart failure worse
Rhythm control
Improving heart efficiency can improve symptoms
How to improve heart rythm?
Beta blockers
