cardio Flashcards
EKG numbers
PR interval
P-R interval = 0.12- 0.2 seconds
3-5 teeny boxes
cardiac output formula
normal # for middle age sednetary person
Q = HR * SV
5L/min
why does contractility affect CO?
contractility of heart based on SR releasing Ca (contraction) and reabsorbing Ca (relaxing). if heart does not fully relax, it cannot take up enough blood
preload
crossbridging (max crossbridging = max preload)
afterload definition
amt of resistance heart faces moving blood forward
what kind of ventricular dysfunction is associated with decreased exercise tolerance? why?
right sided ventricular function because enough blood is not being sent to lungs to be oxygenated
VO2
normal number
oxygen consumption = 10mets =
35mL O2/kg bdy wt/ min
RPP
formula
why we care
rate pressure product
=SBP * HR
if it doesn’t increase as you exercise this should increase otherwise may be sign of ischemia
fatty streak (3)
- earliest visible atherosclerotic lesion
- do not disturb blood flow because they don’t go into the lumen
- from foam cells derived from lipid filled macrophages
fibrous plaque (2)
- more advance lesions that project into lumen => affect blood flow.
- these foam cells are derived from smooth muscle
complicated lesions (types) (4)
- calcification
- rupture of a fibrous plaque
- hemorrhage
- embolization
fibrous cap
extracellular C.T. embedded in smooth muscle. separates the atrial lumen from cell debris
calcification of fibrous plaque issues
result in pipelike rigidity of wall which increases fragility and decreases elasticity
rupture of a fibrous plaque
exposes thrombogenic material into circulating blood
embolization of fibrous plaque results in… (3)
can result in stroke, PE or MI
role of endothelial wall (3)
and what happens if injured
what happens if weak
- causes vasodilation
- resists formation of clots
- inhibits smooth muscle cell migration
if injured: if injured these things don’t happen which lead to clots on the surface
if weakened in spots vessel may burst = aneurysm which can lead to MI or tompenade
AHA cholesterol recommendations
- total cholesterol
- LDL if no heart disease
- LDL if heart disease
- HDL, and a positive number
- total cholesterol < 200 mg/dL
- LDL if no heart disease < 130 mg if no heart disease
- LDL if heart disease > 100mg/ dL
- HDL > 35mg/dL - >60 gives a beneficial result
classification of hypertension
- normal
- high normal
- stage I HTN
- Stage II HTN
- Stage III HTN
- Stage IV HTN
what’s considered uncontrolled HTN for normals and diabetics? and how does it affect PT?
SBP DBP
- normal - 120-129 80-84
- high normal 130-139 85-89
- stage I HTN 140-159 90-99
- Stage II HTN 160-179 100-109
- Stage III HTN 180-189 110**-114
- Stage IV HTN >200** >115
SBP > 200 or DBP > 110 is considered uncontrolled HTN and we do not exercise pt. (110 at exercise or rest!)
SBP >180 for diabetics is considered uncontrolled
how do we classify stage of HTN
by the highest stage - either SBP or DBP (eg 120/99 is stage I HTN because the 99)
during exercise- at what BP do we stop?
230/110***
DBP should not get above 110 during exercise or rest
how does diabetes affect the heart?
postulated that there is increased platelet adhesiveness due to diabetes
blood glucose levels
- normal fed
- normal fasting
- diabetes - fed and fasting- whats considered impaired
when do we stop diabetics from exercise?
when do we check for ketones
- normal fed - 70-110 mg/dL
- normal fasting - 125 mg/dL or 110 fasting
we stop diabetics at >300 mg/dL, at >260 check for ketones in urine
BMI formula
bdy wt (kg)/ height ^2
stable angina
description of symptoms
what we see on EKG
can we treat pt?
- chronic pattern of transient chest pain, precipitated by phsical activity, eating, or emotional upset- relieved w/i minutes
- transient shifts of ST segment (usually elevated)
- treatment is ok
unstable angina
description of symptoms
what happens if untreated
- increased frequency and duration of angina, after less exertion or at rest
- usually => MI if untreated
variant angina
etiology
what we see on EKG
- results from coronary artery vasospasm (vs. increased O2 demand) ** therefore more autonomic dysfunction and not exercise dependent, so happens at rest**
vasospasm can still cause MI* - associated with transient shifts of ST segment (usually elevated)
who is most at risk for variant angina?
women
ischemia
what happens if vessel is 70% stenosed?
what happens if vessel is 90% stenosed?
- at 70% stenosis vessel needs to be completely dilated to achieve adequate perfusion
- at 90% stenosis at constant ischemia, not able to meet basal requirements, hopefully collateral circulation kicks in here
MI
definition
condition of irreversible necrosis of heart muscle that results from prolonged ischemia
transmural MI aka whats anatomy is affected EKG mortality rates
- aka Q-wave MI or ST elevation MI
- full thickness of myocardium- this is what increases Q wave because signal gets to heart wall then has to go all the way around to healthy tissue
- EKG- elevated ST
T becomes pointy & inverts w/i days
QRS widens permanently - High because sudden change in pumping capabilities
subendocaridal MI aka what anatomy is affected EKG mortality/ reinfarction rates
- aka non-Q wave MI
- exclusively innermost layer of muscle (which is most easily affected because it is furthest away from coronary ateries)
- EKG: inverted T
depressed ST - high rates of re-infarction
EKG - QRS duration
What does it mean if wide?
QRS complex = 0.04 - 0.1 seconds
1-2.5 teeny boxes
If wide- beat starts below AV node