Drugs for Heart Failure Flashcards
What is the definition of heart failure?
- an abnormality of cardiac structure or function leading to the failure of the heart to delivery oxygen at a rate that fulfills the requirements of the tissues in the body
Most patients with heart failure have ____
high blood pressure and an enlarged heart muscle and chamber
What happens to the ejection fraction during heart failure?
- it is low
- the percent of blood that is pumped from the body decreases, so the heart does not provide adequate perfusion to the body
What predisposing illness can lead to heart failure?
heart attacks
diabetes
other diseases
Explain the steps of the heart pumping blood to the body
- starts with ventricle diastole/isovolumetric relaxation
- ventricular filling occurs (ventricular diastole)
- atrial contraction/systole occurs
- isovolemic/isovolumetric contraction
- ventricular contraction (ventricular systole-first phase)
- ventricular ejection (ventricular systole- second phase)
What determines the function of the heart?
ejection fraction
What ejection fraction constitutes heart failure?
less than 50%
What is systole? Diastole?
Systole: ventricles contracting
Diastole: ventricles relaxing
Describe how ejection fraction is calculated?
ejection fraction = (amount of blood pumped out of ventricle/ total amount of blood in the ventricle)
How do cardiomyocytes respond to action potentials?
- respond by depolarizing the membrane
- starts by shortening of contractile proteins and ends with relaxation and return to resting state
- cardiomyocytes are interconnected in intercalated discs that respond to stimuli as a unit
What is echocardiography?
- sends sound waves into the body which are reflected at the interfaces between tissues
- return time tells us the depth of the reflecting surface
Force of muscle contraction is related to the amount of what?
cytosolic Ca
What triggers the release from SR and mitochondrial stores?
Ca coming from outside of the cell
How is muscle relaxation in the heart occur?
- achieved through removal of free Ca by the Na/Ca exchangers ad reuptake into SR and mitochondria
What are some of the risk factors and comorbidities that contribute to the development of HF?
- age
- smoking
- obesity
- hypertension
- coronary artery
- diseases like diabetes and dyslipidemia