cardiac failure Flashcards
Explain the Renin angiotensin cascade
a decrease in blood pressure or in renal perfusion is detected by the cells in the kidney and they trigger the release of renin
Renin converts angiotensinogen released by the liver into angiotensin 1, which is converted by ACE to angiotensin 2
angiotensin 2 acts on the adrenal glands and stimulates the release of aldosterone which stimulates salt and water retention
it also causes the constriction of the efferent arterioles of the glomerulus and causing an increase in GFR and blood pressure
lastly it acts on the Pituitary gland and stimulates the release of ADH which stimulates water retention
side effects of ACE inhibitors
chronic dry cough
hypotension
hyperkalemia
why should the combination of spironolactone and ACE be used cautiously
Main mechanisms contributing to hyperkalemia with ACEi/ARB include decreased aldosterone concentrations, decreased delivery of sodium to the distal nephron
Spironolactone is a K+ sparing diueretic this will lead to hyperkalemia if they were to be combined without caution
clinical features of ACE induced ACE-I induced angioedema
tongue, lips and face swelling
why don’t we just use ARB instead of ACE inhibitors
lower risk of death
lower risk of arrhythmias
mechanisms of ACE inhibitors
they inhibit ACE, thus inhibiting the conversion of AG1 to AG2 in order to decrease blood pressure
how do ACE inhibitors cause angioedema and coughing
ACE- inhibitors inhibit the breakdown of bradykinin leading to its increased effects
rising levels of bradykinin, a vasodilator that triggers blood vessels to widen and become more permeable, leading to swelling.
which beta blockers are recommended and why
carvedilol
which heart failure patients should be treated with beta blockers
stable grade 2 or 3 patients or their condition may deteriorate further
contraindications of beta blockers
Asthma 2nd or 3rd AV block Peripheral arterial disease symptomatic hypotension heart rate less than 60
mechanism of action of beta blockers
the block the effects of epinephrine causing the heart to beat more slowly and with less force
which beta blockers are recommended and why
carvedilol, because it has vasodilating properties also
major safety concerns with spironolactone
hyperkalemia
affinity for steroid receptors- gynecomastia, hirsutism, sexual dysfunction
why should we not stop beta blockers abruptly
that can lead to ischemia and infarction
why are beta blockers used rather than calcium channel blockers
beta blockers can prevent heart attacks and death
