Cardiology Flashcards
define atherogenesis
formation of plaque in the artery walls
what is atherosclerosis
this is a result of atherogenesis. it is the narrowing of artery walls due to fatty deposit. it is the principle cause of heart attacks, strokes and gangrene
which arteries are more commonly proned to atherosclerosis
Circumflex, Left anterior descending (LAD) (bifurcation of the LCA) and right coronary arteries
what are the risk factors of atherosclerosis, could you think of why?
Age - biggest determinant Tobacco smoking High Serum cholesterol Obesity Diabetes Hypertension Family History
what is the theory used to describe the mechanism of atherosclerosis? how does it lead to the build up of plaque?
endothelial cell injury. It results in endothelial dysfunction. signals are then sent to circulating WBC which accumulate and migrate to wall vessel, under the cell wall as WBC go through transmigration. this leads to inflammation
what is atherosclerotic plaque made up of
Lipid - due to gradual accumulation of fatty acids to arterial wall (more susceptible to damaged areas)
Necrotic core - from damage site
Connective tissue
Fibrous “cap” - layers of smooth muscle cells that protect blood from contacting endothelial cell and avoiding further breakage
what are the 4 stages of atherosclerosis
1 - fatty streaks
2 - intermediate lesions
3 - fibrous plaques/ advances lesions
4 - plaque rupture
what components are involved in fatty streaks
Lipid laden macrophages (dead macrophages with cholesterol in them)
T-lymphocytes (as a result of inflammation)
what components are involved in intermediate lesion
components in fatty streaks,
vascular smooth muscle cells (that grow out from endothelial cell)
aggression of platelets to vessel wall
isolated pools of extracellular lipids
what occurs in advance lesion stage/ fibrous plaques
impedes blood flow
prone to rupture
covered by dense fibrous cap triggered by smooth muscle cells
give examples of some cytokines you may find in an atherosclerotic plaque
IL-1
IL-6
IL-8
C-reactive protein
what is restenosis
the recurrence of abnormal narrowing after corrective surgery
what is an ECG
a surface examination of the heart measuring its rhythm and electrical activity.
what can you identify from an ECG?
arrhythmia MI and infarction pericarditis chamber hypertrophy Electrolyte disturbance drug toxicity
what is the intrinsic rate of the SA node
dominant pacemaker: intrinsic rate of 60-100 beats/minutes
what are the 2 back up pacemakers called and what are their intrinsic rates
AV node - 40 - 60 bpm
Ventricular cells - 20-45 ppm
what type of deflection is produced by electrical impulses that travel towards the electrode
upright, “positive”
what does one small box and one large box represent on a ECG paper (horizontal)
large box - 0.2sec
small box - 0.04sec
what does one large box represent on an ECG paper (vertical)
0.5 mV
how long should a PR interval be
3 to 5 little squares - 0.12-0.2sec
when is the width of the QRS complex considered wide
when it exceeds 110ms, which is more than 3 little squared
true or false - QRS and T waves always tend to have the same direction in all limb leads
true
in which lead are all the waves negative
aVR lead
what is the normal duration and amplitude of a p wave
less that 3 small squares duration
less than 2.5 small squares in amplitude
