Ischemia Flashcards
What are some causes of ischemic heart disease?
narrowing of arteries: - atherosclerosis - severe HTN/tachycardia - coronary artery vasospasm - hypoxia - severe hypotension - anemia - severe AI or AS
Clinical manifestations of IHD
- angina pectoris - myocardial ischemia/infarct - arrhythmias - ventricular dysfxn - sudden death
Risk factors of IHD
-male -elderly -sedentary -genetic - smoker - DM -dislipidemia -HTN - CAD/vascular disease -obesity - high estrogen BC - menopause - type a personalities
your patient has an occlusion of the RCA. What part of the heart is affected and what leads would you see changes?
Inferior wall changes in II, III, avF
your patient has an occlusion of the Left circumflex. What part of the heart is affected and what leads would you see changes?
Lateral wall changes in I, aVL, V5, V6
your patient has an occlusion of the Left anterior descending coronary artery. What part of the heart is affected and what leads would you see changes?
Anterior
V1-V4
Ischemic heart disease is characterized by:
imbalance between O2 supply and demand
Define atherosclerosis
Fatty substances such as cholesterol, cellular waste products and calcium build up in the lining of arteries.
what substances are released during ischemia? what are the actions of these substances?
bradykinin and adenosine.
- Chest pain (thalamic and cortical stimulaion)
- Slow AV node conduction, decrease contractility (balance O2 supply demand)
What is the difference between stable and unstable angina?
Unstable angina is any new changes in chest pain (longer duration, increased frequency, not relieved by NTG, precipitating factors ie used to walk 3 blocks before SOB, now can only walk 1 block)
Unstable angina is a signal for:
impending MI. don’t take the pt to OR!!
What is stunning, hibernation and preconditioning?
Stunning- brief periods of ischemia the resolves in several hours
hibernation - ongoing dysfunction d/t impaired coronary blood flow. resolves with return of blodo flow.
preconditioning - intermittent periods of ischemia to provide protection against larger ischemic events (exercise, pacers, opioid, volatile anesthetics)
How do the volatile anesthetics we use precondition the heart for ischemic events?
block the triggers
Prinzmetal angina is often associated with other vasospastic dz. what are examples?
Raynaud’s, migraine headaches
T/F: Prinzmetal angina can occur in a normal vessel.
True. CORONARY SPASM is the main concern. these spasms don’t discriminate.
lifestyle mods that we can educate our patients about
smoking cessation
diet
exercise
Drugs for managing IHD
Beta blockers - decrease HR/contractility
CCB - dilate coronary arteries, decrase contractility and afterload
ACE-I decrease contractilty/afterload
Nitrates - dilate coronary arteries, collateral vessels, decrease preload (venodilation) and afterload (dec periph vasc resistance)
Antiplatelet - decrease risk for thrombosis
also diuretics
what happens when a plaque ruptures?
- plt aggregation
- thromboxane A (vasoxcx)
- GII/b III/a activation (inc plt aggregation)
- fibrin deposits
- thrombus
- angina, microemboli, infarct, spasm, and/or sudden death
infarction occurs how long after ischemia?
20-30 mins.
reaches full size in 3-6 hrs.
3 criteria for diagnosis of MI
- chest pain
- serial EKG
- inc/dec cardiac enzymes
perform cardiac MRI to determine extent of MI.
how do we treat MI?
eval hemodynamics - check the VS!!
12-lead EKG
O2
Morphine/NTG
ASA/clopidogrel
ACE-I are appropriate adjuncts to therapy if:
- Anterior wall MI (LAD)
- EF <40%,
- Diabetic
Some complications of infarct:
- arrhythmias
- LVF/ CHF, +/- pulm edema
- cardiogenic shock
- thromboembolism - stroke
- papillary muscle dysfxn - valve disease
- external rupture of infarct >>tamponade>>death (4-7 days post)
- ventricular aneurysm
- acute pericarditis (2-4 days post)
Things that decrease O2 supply:
Tachycardia
hypotension
vasoconstriction
dec O2 carrying capacity
acid-base
anemia
hypoxia
viscosity
coronary spasm
