Heart Flashcards
Right coronary artery blood distribution
Inferior wall 2 3 avf
Left ant descending artery
Anterior wall v1-v4
Left circ
1 avl v5 v6. Lateral wall
Lead v5 detection of ischemia
75% up to 90% with v4
Acute mi after surgery with heart block. What side ruptured
Rca because it aupplies 90% of av node. It also supplies inferior wall
Coronary perfusion
When aortic pressure is greater then lvedp
When propofol dilates arteries phenelpherine constricts and leads to increased coronary perfusion by increasing afterllad and decreasing tachycardia
Phenylepherine can constrict coronary arteries but the nitric oxide can in the coronary artery can overcome these weak affects
Epi vs ne on receptors
Both have agonistic affects on alpha 1/2 and b1 but epi also exclusively acts on beta 2. You can remmeber this because epi is given for bronchospasm
Since ne acts on on alpha one and not beta 2 it results in increased sbp and dbp while epi acts on both cause an increase in sbp while decreasing diastolic
Dopamine and renal preservation
Has no clinical afffect in saving kidneys
Hypotensive and cardiogenic
Use ne and dobutamine
Dobutamine does b1» beta 2
Disadvantage of dopamine
Tachyarryjtmias like afib
Both ne and dop stimulate alpha one
Dopamine
Cathecholamine degradation
In liver its comt then mao
In nerve endings its mao then comt
Both produce bma
Dopexamine
Opposite of dobutamine b2»b1
Isopreternol
Used mainly for cardiac stimulation
Dopamine vs dobutaminr
Dopamine more increase in tachycardia compared to doubutamine
Dromotropy
Increases conductance through cardiac fibers
Lusitropy
Means relaxation of the heart
Beta receptors via
G protoen that turns atp to camp via adenylate cyclase. Leads to increased intracellulsr calcium
Alpha receptor moa
Via phospholipasw c
Nitric oxide moa
Leads to increased cgmp
No leads to methhemoglonemia
Vasopressin
40 units
Increases svr
Svr equation
=map-cvp/co. *80
Nitroprusside
Produces met hgb by taking an electron from fe2+ to fe3+
The notroprusside molexule becomes u stable with additional hgb and breaks into five cyanide molecules and nitric oxide. The nitric oxide goes to stimulate cgmp. The cynaide then either binds to methgb to make cyanamet hgb , bind to cytochorme oxidase or bind with thiosulfate to produce thiocyanate. The thicynate js cleared by kidneys
Nitroprusside affects on ph
By binding to cytochrome oxidase it prevents etc from working and causes anarrobic metabolism. This leads to increased mvo2 becUse cells cant use o2
Treatment is with sodium nitrite. The met hgn can act as a sink for cn- by the production of cyanamet hb.
Classic treatment is thiosulfate which binds to cn producing thiocyanate
Nitroprusside and ards
Can cause pulm shunt that results from vasodialating hypoxic areas
Carotid body
Located at the bifurcation. In by glossopharngeal out by vagus nerve. Promarily affect circulatory changes
Respond to pao2
