6-cardio Flashcards
why can diuretics be good for heart failure (3)
relieve oedema and work load on heart, may have vasodilatory action
what kind of diuretics are thiazides
loop diuretics (high ceiling)
what is an example of a thiazide
furosemide
how does furosemide work
causes K+ loss
what is spironolactone
K+ sparing diuretic
how does spironolactone work
aldosterone antagonist
where is aldosterone released from
adrenal cortex
what does aldosterone release do to K+
increase loss
what does aldosterone release do to Na+
increase retention
what does aldosterone release do to H2O
increase retention
what does spironolactone do to K+
increase retention
what does spironolactone do to Na+
increase loss
what does spironolactone do to H2O
increase loss
what do vasodilators do to preload in healthy subjects
decrease
what do vasodilators do to cardiac output in healthy subjects(and how)
decrease bc decreased preload (frank starling)
what do vasodilators do to veins(in healthy subject)
dilates
what do vasodilators do to arterioles(in healthy subject)
dilates
what do vasodilators do to arterial pressure(in healthy subject)
decrease
what do vasodilators do to afterload (in healthy subject)
decrease
what happens to BP with decreased cardiac output and arterial pressure (in healthy subject)
there is a decrease in BP
what happens to HR with decreased cardiac output and arterial pressure (in healthy subject)
increase (low BP causes BR receptor reflex)
what is the net effect on BP and HR with vasodilators (in healthy subject)
hypotension and tachycardia
why does afterload increase during heart failure
compensatory sympathetic reflexes + increased angiotension = arteriolar constriction
what does high afterload do to output of a failing heart
it may limit output
why can cardiac output increase with vasodilatory agents with CHF patients (compared to healthy patients)
less afterload so the heart will have an easier time pumping out blood
what happens do BP and HR with vasodilators in CHF patients + why
they dont fall and no reflex tachycardia
because reduced peripheral resistance is balanced out by increased cardiac output
where is angiotensinogen released
liver
where is renin released
kidneys
where does angiotensin converting enzyme come from
lungs
what does ACE do
convers angiotensin 1 into angiotensin2
what does renin do
converts angiotensinogen into andgiotension 1
what does angiotension do to vessels
vasoconstrict
what does angiotension do to aldosterone release
increase
where is aldosterone released from
adrenal cortex
what does what does angiotension do to K+
increase loss
what does angiotension do to Na+
increase retention
what does angiotension do to H2O
increase retention
what are 4 main effects of ACE inhibibots (vessels and molecules)
vasodilation
K+ retention
H2O land Na+ loss
what do ACE inhibitors do to angiotensin 2 formation
inhibit
what does angiotension 2 do to bradykinin
prevents its catabolism
what is the role of bradykinin
potent activator of NO release from endothelium
what does bradykinin in lungs do
causes the dry cough that is a side effect of ACE inhibitors
what causes the dry cough with ACE inhibitors
they prevent breakdown of bradykinin which causes dry cough when acting in lungs
besides the cough, what are other bad side effects of ACE inhibitors
makes things taste weird
what are 2 ACE inhibitor drug names
enalapril and captopril
what do enalapril and captopril do in general
stop AG2 synthesis
what do enalapril and captopril do to afterload
decrease
what do enalapril and captopril do to preload
decrease
how can what do enalapril and captopril help with oedema
they increase Na+ and H2O loss (inhibits aldosterone)
what happens to cardiac output in heart failure
decrease
what happens to venous return in heart failure
decrease
what are 2 drugs classes that are often combined to dreat CHF
ACE inhibitor and diuretic
why is it good to use low doses of both ACE inhibitor and diuretic instead of a high dose of 1
you get additive therapeutic effects and less side effects (sometimes side effects cancel out)
which side effects cancel out with ACE inhibitor and diuretic (which diuretics)
thiazide diuretics promore K+ loss and ACE inhibitors promote K+ retention
what is losartan (2 things)
vasodilator
angiotension receptor antagonist
what are amrinone and milrinone (3) +What do they do to vessels and heart
phosphoriesterase inhibitors
vasodilate and stimulate heart
what do amrinone and milrinon do to contraction of heart
increase
what do amrinone and milrinon do to contraction of vascular smooth muscle
reduce
how do beta agonists work on cardiac muscle stimulation
cAMP, PKA, increase Ca++ through L type
if B1 agonist stimulate heart and B2 relax vascular smooth muscle but both are Gs, how does this work?
there are different contractile mechanisms of smooth and cardiac muscle
is myocin light chain kinase in heart
no
is myosin light chain kinase in vascular smooth muscle
yes
how do B2 agonists cause vascular smooth muscle relaxation
elevated cAMP inactivates MLCK by phosphorylating it so then it cant contract
what are dobutamine and dopamine (mechanism of action)
beta1 agonists
why can beta blockers be used for chronic failure (dobutamine and dopamine (b1 agonists) are also used)?
it can help calm down the crazy sympathetic outflow
what are 4 beneficial effects of beta blockers and CHF
- attenuation of adverse effects of high [NA]
- decreased HR
- inhibit mitogenic activity of catecholamines
- lower afterload by reducing renin release
why is it good that beta blockers inhibit mitogenic activity of catecholamines
because sometimes the vessels grow in the wrong areas and stuff which is bad
what receptors does carvedilol target
beta 1
beta 2
alpha 1
all block
what is the benefit of carvedilol over beta blockers
it also lowers afterload (because it blocks alpha1)
what are 4 therapeutic approaches to high BP
- diuretics
- sympatholytic agents
- direct vasodilators
- ACE inhibitors (or any drug that can block production or action of angiotensin)
what do diuretics do to vessels (sometimes)
can vasodilate
what does depletion of Na+ from diuretics do to blood vessels stiffness
help reduce it
what do thiazides to in the kidney (mechanism of action in nephron)
inhibit NaCl reabsorption by distal convoluted tubule
what is metoprolol
b1 selective antagonist
why can metoprolol be better than propranolol
acute vasodilatory action from b2 receptors may reduce effectiveness ( you dont wanna block those )
what are 4 main things that beta blockers do (MECHANISM)
- inhibit renin release
- inhibit presynaptic Beta that usually increase NA release
- reduce sympathetic outflow (possible actions in CNS)
- slows HR during exercise and stress
is it better to work on the angiotensin or adrenergic system to change BP
angiotensin system is connected just to BP while the adrenergic is more linked throughout the whole body (so angiotensin is better)
what class is hydralazine is
vasodilator
what does hydralazine do (3)
arteriolar vasodilation, lowers BP and reflex tachycardia
what do you usually combine with hydralazine and why
beta blocker to help prevent the reflex tachycardia
what is nitroprusside (how and when is it used)
powerful arteriolar and venous vasodilator used in hypertension emergencies
what are 6 types of vasodilators
hydralazine nitroprusside verapamil nifedipine dihydropyridines ca channel blockers
are ca channel blockers vasodilators
yes
what are 3 agents that block the production / agent of angiotensin
captopril
enalapril
losartan
what is captopril
ACE inhibitor
what is enalapril
ACE inhibitor
what is losartan
angiontensin receptor blocker
does captopril make the dry cough
yes
does enalapril make the dry cough
yes
does losartan make the dry cough
no
