PBM Lecture Exam 2 Flashcards
Most coronary blood flow during what stage of cardiac cycle?
diastole
Compare skeletal and cardiac m
O2 debt
anaerobic metabolic
Skeletal
- -O2 debt repaid during rest
- -anaerobic provides 40% of energy during exercise
Cardiac
- -O2 debt rarely incurred
- -anaerobic only used during extreme hypoxia
Atherosclerosis
complex arterial disease in which cholesterol deposition, EC matrix, and thrombus formation play major roles
Atherothrombosis involves…
heart (coronary aa)
brain (carotid, vert, cerebral aa)
aorta
periph aa
if there is a significant underlying coronary epicardial stenosis present,
blood flow at rest is maintained by…
compensatory dilation of coronary bed beyond the stenosis
if there is a significant underlying coronary epicardial stenosis present,
diminished coronary reserve results in
inability to meet O2 requirements as myocardial demand inc –> creates supply/demand mismatch
Stable angina vs unstable angina
stable: vague chest/arm discomfort that is reproducibly associated w/ physical exertion or stress and is relieved w/in 5-10 min by rest of sublingual nitroglycerin
unstable: freq angina, even at rest/minimal exertion – lasts more than 20 min, severe PAIN, occur w/ crescendo pattern (more severe, prolonged, frequent)
how much of coronary a must be blocked for there to be a problem?
70%
Describe physiology of plaque
foam cells
cholesterol builds up in matrix of aa (thin, fibrous caps and lipid rich cores)–> plaque
plaque inflamed and pops –> bleeds
thrombus forms (platelet aggregtion, fibrin deposition, vasoconstriction)–> obstructs a –> MI
another plaque forms over this –> further narrowing
Angina occurs when myocardial work load (O2 demand) ____ the capacity of myocardial blood supply (O2 delivery)
when O2 demand exceeds O2 delivery
Clinical presentation of angina
symptoms provoked by: 4E's -exertion -eating (heavy meals) -emotional distress -environment symptoms reproducible and present for prolonged period of time
CAD symptoms experienced by women
back right side weak sweats nausea atypical pain
Risk factors for CAD
obesity BP carotid bruit dec periph pulses S4 sounds may have normal ECG
Areas where angina pain radiates
neck jaw upper abdomen shoulders arms
Diagnose CAD using
cardiac risk factors ECG Chest X ray stress test angiography guided therapy
Stress test – should achieve what percent of max predicted HR
Max predicted HR =
85% of MPHR
MPHR=220-age
Pos stress test
New ST segment depression early into exercise
New ST segment depression >2mm in multiple leads
Inability to exercise more than 2 min
Dec systolic blood pressure w/ exercise
Development of heart failure or sustained vent arrhythmias
Prolonged interval after exercise cessation (>5 min) b/f segments changes return to baseline
Determinants of myocardial O2 demand
HR
afterload / systemic vasc resistance
myocardial wall stress (measured by preload)
myocardial contractility
Angina treatment
ABCDE Treatment:
Aspirin (antiplatelets, antianginal – nitrates)
Beta blockers (reduce HR and BP)
Ca channel blockers, cholesterol (statins), Cigarette smoking
Diet (low cholesterol, dec salt intake)
Exercise
ECG findings in angina pts
normal in 50% of pts abnormal: --ST abnormalities --Q waves --LVH --T wave inversions
Biochem markers for angina pts
CBC (anemic? – GI bleed?)
FBS (glucose)
troponin
lipid profile
Side effects of beta blockers
fatige
impotence in men
STEMI
ST-segment elevation myocardial infarction
–MI as myocyte cell death due to prolonged ischemia
Clinical definition of MI
2 of the following:
characteristic symptoms
elevation in cardial biomarkers (troponin)
characteristic ECG changes
