Drugs for Heart Failure Flashcards
(35 cards)
define heart failure
- refers to the inability of the heart to pump enough blood to satisfy the body’s demand for oxygen
what are some leading risk factors for heart failure?
- CV disease
- previous MI
- chronic hypertension
- diabetes
- mitral stenosis
- cardiomyopathies
- congenital heart disease
define preload and what causes an increase in preload?
- the degree to which the muscle fibres are stretched before the heart contracts
- an increase in blood volume may be because of fluid retention
- increase in venous pressure or increased ventricular compliance that results in greater filling of the ventricle
what causes pulmonary edema?
- increased preload can cause failure of the left side causing blood to back up into the pulmonary system
- fluid leaves the pulmonary capillaries and goes into the alveoli and interstitial of the lung causing edema
what causes decreased oxygen supply?
- fluid collection causes congestion and shortness of breath
- fluid reduces the ability to exchange gas and results in decreased oxygen supply
what causes decreased myocardial contractility/stroke volume and cardiac output?
- results in lower blood pressure causing less blood flow to the kidneys which activates the RAA pathway and causes release of ADH
- ADH and aldosterone causes water and sodium retention and aldosterone also increased peripheral resistance
what happens when after load increases due to an increase in peripheral resistance?
- causes blood to back up into the peripheral circulation resulting in edema in limbs
what is diastolic dysfunction?
- left ventricle has become stiff, the heart cannot relax and cannot fill up as much causing less blood in the ventricle and pumps out less
- caused by loss of elasticity/contractility
- the heart compensates by increasing muscle mass or dilate to increase blood flow
what is systolic dysfunction?
- loss of contractility in left ventricle causing less ejection of blood
what are some less common symptoms of heart failure?
- cognitive impairment
- altered mentation or delirium
- nausea
- anorexia
- oliguria
- cyanosis
what are the 9 drug classes that are used to treat heart failure?
- ACE inhibitors
- adrenergic blockers
- loop diuretics
- vasodilators
- phosphodiesterase inhibitors
- cardiac glycosides
- angiotensin receptor neprilysin inhibitors
- Ivabradine
- aldosterone antagonists (potassium-sparing diuretics)
what is the mechanism of action of ACE inhibitors?
- reduce blood pressure and decrease cardiac workload
- reduces fluid retention via inhibitor of the RAA pathway
what is the mechanism of action of adrenergic blockers?
- alpha and beta blockers lower blood pressure and reduce heart rate
- decreases workload of the heart by decreasing afterload
what is the mechanism of action of loop diuretics?
- increased urine output lowers blood volume and therefore preload and cardiac workload
what is the mechanism of action of vasodilators?
- acts on arterioles to decrease peripheral, reduce afterload, and increase stroke volume and cardiac output
- reduced preload by dilating veins and reducing venous pressure
- decreased proximal capillary hydrostatic pressure which reduces capillary fluid filtration and edema formation
what is the mechanism of action of phosphodiesterase inhibitors?
- increases contractility in the heart increasing stroke volume
- drug is fast acting and is administered IV, with constant monitoring by ECG
what is the mechanism of action for cardiac glycosides?
- slows the heart rate and increases force of contraction
- used in more serious cases of HF
what is the mechanism of action of cardiac glycosides?
- slows the heart rate and increases force of contraction
- used in more serious cases of HF
what is the mechanism of action of angiotensin receptor neprilysin inhibitors?
-valsartan inhibits the effects of angiotensin II at its receptor, inhibiting both arteriolar contraction and the sodium retention effects of RAA system
what is the mechanism of action of Ivabradine?
- inhibits the “IF” channel pacemaker current in the SA node, lowering heart rate and increasing blood to flow to the myocardium
when is ivabradine used?
- the symptomatic management of HF in patients who are not on beta blockers or already receiving the max beta blocker used
what is the mechanism of action of the aldosterone antagonists (potassium-sparing diuretics)?
- blocking the action of aldosterone, mineralocorticoid receptor antagonists enhance the excretion of sodium and the retention of potassium resulting in diuresis
- reduces the mortality rate in clients with HF
why is it important to take daily weights while on a diuretic drug?
- detecting the onset of volume overload
what is daily weight gain due to?
- fluid retention and can lead to crisis if symptoms are not managed
