Acute Coronary Syndrome Flashcards
RCA
1) cardiac muscle supplied (mechanical)
2) conducting tissue supplied (electrical)
1) R atrium/ventricle, portion of posterior and inferior surface of L ventricle
2) 55% SA node, 90% AV node
LAD
1) cardiac muscle supplied (mechanical)
2) conducting tissue supplied (electrical)
1) anterior wall of right and left ventricles, intraventricular septum
2) bundle branches
Circumflex artery
1) cardiac muscle supplied (mechanical)
2) conducting tissue supplied (electrical)
1) L atrium, L lateral ventricular wall
2) 45% SA node, 10% AV node
modifiable risk factors - cardiac
- smoking
- HTN
- T2DM
- obesity
- physical inactivity
- cholesterol
non modifiable risk factors for cardiac disease
- age > 55yrs for male, 65 yrs for female
- sex
- family hx
- ethnicity (south asian, african)
acute coronary syndrome
any constellation of clinical signs or symptoms suggestive of acute MI or unstable angina
what causes signs and symptoms to present in ACS?
imbalance in coronary oxygen supply and demand lasting greater than 10 mins
continuum of ACS
1) stable angina
2) unstable angina
3) NSTEMI
4) STEMI
unstable angina
- unanticipated, occurs at rest, might be transient and ECG could be normal.
- chest pain = 10-20mins
- ischemic event is not severe enough to cause myocardial necrosis
- may be temporary ST segment depression or T-wave inversion
- does not release cardiac biomarkers; no cell death
NSTEMI
- chest pain is greater than 20mins
- ischemic changes associated with ST depression or T wave inversion persisting after pain is relieved
- release of cardiac biomarkers and cell death occurs
- usually partial occlusion
STEMI
- severe chest pain lasting greater than 30 mins
- ischemic changes that are associated with ST elevation
- release of cardiac biomarkers and cell death occurs
- usually full occlusion
angina pectoris
chest pain that is cardiac in origin. crushing chest pain with radiation down left arm
atypical presentation of ischemic symptoms include ______ and are more common in _____
- SOB, weakness, fatigue, cold sweats, n/v, indigestion, doom, neck pain
- women, elderly, people with diabetes
angina pectoris s&s
- beneath sternum radiating into jaw/neck
- upper chest
- beneath sternum radiating into left arm
- epigastric/radiating into neck, jaw, arms
- left shoulder, inner aspect of both arms
- intrascapular
referred pain with angina pectoris
heart shares dermatomes with other areas of the body, so the brain perceives the pain as coming from other areas; may think cardiac pain is jaw, arm, neck discomfort
physiology of chest pain
ischemia -> chemoreceptors and mechanoreceptors activated in the heart -> stimulation of pain receptors -> signal to brain -> pain occurs
when are chemoreceptors activated in the heart?
when bradykinin is produced
when are mechanoreceptors activated in the heart?
when ischemic injury occurs (edema, myocardial stretch)
silent ischemia
- non painful ischemia common in older adults and diabetics
- you have defective afferent nerves and an increased pain threshold with reduced pain sensitivity hence no pain
layers of the vessels of the heart
1) tunica adventitia (CT)
2) tunica media (muscle)
3) tunica intima (endothelium)
role of endothelium
- prevents thrombus formation
- mediates immune and imflmtry response
- regulates vascular tone and growth
plaque formation
- atherosclerosis occurs as a result of endothelial injury
- chronic inflammatory condition
what can endothelial injury be caused by?
- cardiac risk factors
- chronic inflmtn from bacteria, viruses
- ineffective shear stress
pathogenesis of endothelial injury
injured endothelium = fatty streaks build up consisting of cholesterol, calcium = evolve into fibrous plaque that builds up in arterial lumen = causes thrombus formation and blocks artery = release of less nitric oxide which is a vasodilator and platelet inhibitor