Axis Determination etc. Flashcards
what do the limb leads show?
the depolarization of the heart in the frontal or coronal plane
what do the precordial leads show?
the depolarization of the heart in the horizontal plane
if there is a partial occlusion of a coronary artery, what might you have?
unstable angina or NSTEMI
what do you have if coronary flow is occluded?
STEMI
what is the progression of CAD/ACS?
normal heart-> stable angina-> unstable angina-> NSTEMI-> STEMI
what are the zones of infarction?
infarction, injury, and ischemia
what is the zone of infarction and how is it represented on the ECG?
it is the area of dead tissue and it lack depolarization; Q waves
what is the zone of injury and how is it represented on the ECG?
deficient blood supply and inability to fully polarize; ST segment shifts
what is the zone of ischemia and how is it represented on the ECG?
deficient blood supply and impaired repolarization; T wave changes
what are the T wave changes associated with myocardial ischemia?
inverted T waves, tall peaked T waves, depressed T waves
when is troponin detectable after an AMI?
1-4 hours after onset
when is the peak of troponin after an AMI?
10-24 hours after onset
how long does troponin persist after onset of AMI?
5-14 days
what could cause false positive troponin levels?
renal failure
what is the elevation criteria for a STEMI?
ST elevation of 2mm or more at the J point in V2-V3 or 1mm or greater in 2 or more contiguous chest or limb leads; could be STEMI if there is a new LBBB
