Cardio 3 Flashcards
what two mechanisms do organs have for controlling their own blood supply?
1) myogenic mechanism (walls of vessels are stretched, and put out sm mm dilators to increase flow and reduce press)
2) metabolic mech
(match supply w/ demand; dials up blood flow when metabolic waste products dilate nearby vessels to allow more flow)
what hormone causes coronary auto regulatory vasodilation?
adenosine
Coronary blood flow formula?
CBF = (art DP - LVEDP)/ coronary resist
which part of the heart muscle is MOST vulnerable to ischemia?
ENDOCARDIUM
what is NORMAL Cerebral Blood Flow (CBF)?
50mL/100g/min
what’s Cerebral Perfusion Pressure, and how does it relate to CBF?
CPP = MAP - CVP
(as long as CVP>ICP)
CBF=CPP/CVR
Cushing reflex?
maintain MAP in face of high ICP…still push blood in despite high ICP…..bradycardia follows….HERNIATE NEXT!!!
(DON’T WANT TO SEE THIS….CATASTROPHE)
PaO2
….augment CBF
PaCO2 on same graph
STRAIGHT LINE
renal blood flow regulated by what two mechs?
1) myogenic
2) tubuloglomerular feedback (TGF)
what is TGF?
autoreg function mediated by macula densa; sense higher NaCl, promote constriction of afferent arteriole to decrease Blood flow
post-prandial hyperemia?
- augmented blood flow to splanchnic circulation
- mucosal metal
- vasoactive GI hormones
splanchnic circulation contains how much of Blood vol?
15%
–source of systemic volume in times of need
uterine vascular autoregulation
NOT THERE. vessels are maximally dilated; perfusion is PRESSURE dependent
DIGOXIN mechanism?
- blocks Na/K pump
- INCREASE intracell Na
- Na/Ca exchanger that drives Ca outside (bc decreased Na gradient to come back in) decr
- More Ca intracell
- INCREASED contractility
what does digoxin do at AV node?
decreases conduction
K decreases
digoxin toxicity
-tachydysrhyth
-bradycardia
-potentiated by hypo/hyperkalemia
DIURETICS - WATCH!!
MC EKG finding of digoxin?
PVC
what other finding on EKG that’s typical of digoxin?
- “hockey stick”
- scooped out QT
treatment of Ventricular arrhythmias with Dig?
- lidocaine
- amiodarone
- Potassium (upper normal)
- LOW ENERGY only if cardiovert
- can give Ab
Adenosine to treat what?
- WPW
- SVT (narrow)
How adenosine work?
- coronary vasodilation
- AV NODAL SUPPRESSION
antagonism of adenosine?
METHYLXANTHINES
- caffeine
- theophylline
- amrinone
SE to adenosine?
bronchospasm!!
amiodarone chemically similar to what endogenous hormone?
thyroxine
Amiodarone does WHAT to nodes?
depresses both SA and AV
heart toxicities of Amio?
- hypoTN
- Sinus Brady
- heart block
- QRS/QT prolongation
- depress contractility
other SE of amio?
- hypoTHYroid
- thyrotoxicosis
- pulm fibrosis
- CNS (periph neuron)
- LFT incr
- BLUE SKIN
QT prolong drugs!
- zofran
- haldol
- antiarrhythmics (sotalol, amio, procainamide)
- antifungals
- ABX: TMPSMX, erythro, pentamidine
- ANTI-depress: amitrip, doxepin
alpha 1 receptors located where in relation to synapse?
-POSTsynaptic
how coupled with protein?
- Gq protein coupled
- activate Phospholipase C
- PIP2 to IP3 plus DAG
Alpha 2 receptors located where in relation to synapse?
-PREsynaptic
coupled how?
- Gi Protein coupled
- INHIBITS Adenyl Cyclase
- ATP to cAMP
all beta receptors located WHERE in relation to synapse
POST-synaptic
all Beta receptors coupled how?
- Gs protein
- activates Adenyl Cyclase
- atp to cAMP
what is dromotropy?
increase impulse conduction
beta 1
what is word for increase contraction?
inotropy
Dobutamine as pressor, hits what receptors?
B1, B2
-INCREASE CO
what can happen if use dobutamine alone?
get hypotension; use with another agent if already hypotense
SE of using for a while
- tachyphylaxis
- arrhythmogenic
Dopamine - which receptors?
LOW - DA
High - a1, a2, B1
why use Epi for anaphylaxis?
prevents mast cell degranulation
metabolic SE of epi?
hyperglycemia
What is reflexive effect of NE?
brady
how is NE metabolized?
- MAO
- COMT
NE unique for redistributing blood where?
- brain
- heart
Vasopressin effects on what receptors?
V1, V2
Selegiline = what kinda drug?
MAOI
what drug should NOT be used with MAOI’s?
ephedrine
indirectly acting sympathomimetic Amine
Isoproterenol
synthetic catecholamine NO ALPHA -b1, b2 -DECREASE after load -DECREASE Pulm Vasc Resist
GOOD pressor for NEUROGenic shock
-dopamine
mechanism of MILRINONE?
- increases myocytes’ intracell cAMP by inhibiting PDE3 from breaking it down
- get INCREASED:
- -inotropy
- -lusitropy
- -chronotropy
- -dromotropy
- -automaticity
what does milrinone do is vascular beds?
vasodilation
-Also good for DECREASED Pulm VASC RESIST
nitroglycerin mech?
- direct vasodilator (veins»arteries)
- relieves coronary spasm
nitroprusside becomes?
NO (so relaxes smooth muscle)
what’s harmful toxin from it?
-cyanide
hydrazine mech?
K+ channel ACTIVATION on sm mm; causes depolar and relaxation
bad rare SE of hydralazine?
- lupus like syndrome
- agranulocytosis
CCB work where?
cardiac effect OR vasc smooth muscle
- -vasodilation
- -slow nodal conduction and inhibit contractility
which 2 CCB better for vasodilating effects?
- nifed
- nicard
CCB more cardiac effects?
Verapamil
also Dilt
Verapamil + BB?
BAD = can cause death
ACE good for heart how?
- cardiac remodeling
- renal protection
ACE SE?
-hyperkalemia
(bc it’s inhibit aldost??)
-ANGIOedema [bradykinin; cough, too]
ACE in preggers?
NO NO NO!!!
category D
hypokalemia on EKG:
- depressed T
- U-wave prominent (big hill AFTER t-wave)
- somewhat prolonged PR
sxs of hypoKalemia?
- myalgia
- FLACCID PARALYSIS
- hyporeflexia
- resp weakness
HYPERkalemia on EKG?
- peak T-wave
- prolong PR
- VFIB
Tx for hyperkalemia?
- Ca Gluc
- Insulin + Glucose
- furosemid
- Kayexalate
- hemodialysis
HYPOcalcemia Ekg
LOW level - LONG QT
HYPERcalcemia EKG
HIGH Ca
SHORt QT
Ca too low, can cause what heart ailment?
-CHF
TOO much Ca to heart?
arrhythmias
Tx for hypercalcemia?
- diuresis
- calcitonin
- dialysis
HYPO Magnesium?
- chvostek’s sign
- Trousseau’s phenom
HYPERmagnesemia?
- -TALL t-waves
- -depressed ST
Tx INCR mag?
- calc gluc
- diuretics
- dialysis
