Flashcards in CV Resp Deck (43)
How does the ductus arteriosus normally close?
when baby takes first breath theres an increase in O2 which causes a decrease in prostaglandin production > closure of DA
What are the energy sources of the heart?
1. Fatty oxidation (60%)
2. Glucose oxidation
what is the most posterior part of the heart?
calculate CO using rate of o2 and such
= rate of O2 consumption/arterial O2 content - venous O2 content
What happens when theres a wide splitting of A2/P2?
seen in conditions that delay RV empyting: pulmonic stenosis and right bundle branch block
What happens when theres a paradoxical splitting of A1 and P2?
seen in conditions that delay LV emptying (aortic stenosis, left bundle branch block), normal valve closure is reversed since LV is trying to empty for a longer period of time
When can you hear an S3 the best?
left lateral decubitus position during exhalation
What murmurs are heard better w valsalva?
MVP and hypertrophic cardiomyopathies
(it decreases preload and afterload)
- decreases the intensity of most other murmurs
How does hand grip affect murmurs?
it increases afterload: increases intensity of MR, AR, VSD, MVP
How does the murmur of MVP change w position?
Standing up: decreases preload, click closer to S1
Lying down: increases preload, click and murmur closer to S2
Marfans pt dies slowly bc of a heart issue, what is it?
MVP- leading to conductive issue
left infraclavicular murmur loudest at S2
PDA: congenital rubella or prematurity
what phase of the cardiac AP does cardiac muscle contractoin occur?
How do ACh and adenosine act on the pacemaker AP?
they decrease the rate of diastolic depolarization and decrease HR
Speed of conduction?
purkinje, atria, ventricle, AV node
how do T waves relate to K?
Hyperkalemia = peaked T waves
Hypokalemia = flat T waves
how do you treat A flutter?
1. Class IA, IC, or III antiarrhythmics
2. Rate control: betal blocker or Ca channel blocker
What can cause a first degree AV block?
lyme disease- but more likely causes third degree heart block if not treated
where does ANP act in the kidney?
causes decreased Na reabsorption at the medullary collecting tubule
- constricts efferent arteriole and dilates afferent arteriole via cGMP
- contributes to the escape from aldosterone
delta wave on ECG
wolf parkinson white syndrome: acessory conduction pathway that bypasses the AV node leading to early ventricle depolarization
- also see a slurred upstroke of QRS
tx: Procainamide or amiodarone
where do the aortic arch and carotid sinus receptors send their info?
to solitary nucleus of medulla
What happens in supine hypotension?
supine or right lateral decubitus position > compression of IVC > reduced venous return, reduced preload, reduced CO and hypotension
Tricuspid atresia: what is it?
absence of tricuspid valve and hypoplastic RV
- requires both ASD and VSD for viabiliity
boot shaped heart
tetrology of fallot
how do pts with tetrology of fallot relieve cyanotic spells?
they squeat to increase PVR and decrease the right to left shunt
why are beta blockers the drug of choice for aortic dissections?
decrease the slope of rise in BP
how do you diagnose prinzmetals angina?
how do you reverse a hibernating myocardium?
Time course microsopically of MI: contraction bands from reperfusion injury, release of necrotic cell content into blood, beginning of neutrophil migration