myocardial ischemia and infarction

Question 1

what is myocardial ischemia?

Answer 1

decreased blood flow (one of the consequences of CAD)

Question 2

what does myocardial ischemia lead to?

Answer 2

hypoxic cells-chest pain AKA angina pectoris

Question 3

what is the treatment for myocardial ischemia?

Answer 3

medications, or invasive surgery

Question 4

hat is the medication treatments for myocardial ischemia?

Answer 4

nitrates-vasodilation
morphine-SM relaxant, vasodilation
b-blockers/Ca+ channel blockers-vasodilation, decrease heart rate and force of contraction

Question 5

what are the invasive surgery options for treatment of myocardial ischemia?

Answer 5

angioplasty-stent
coronary bypass-sewing a graft from the aorta to the coronary artery bypassing the obstructed vessel

Question 6

what is MI?

Answer 6

prolonged myocardial ischemia (4-6 hrs) leading to cell death

Question 7

how is MI exasterbated?

Answer 7

by the SNS response increasing work load

Question 8

what are the causes of MI?

Answer 8

decreased cardiac output
damning of the blood in Venus system
reputed infarct
ventricular fibrilation-dysrhythmia

Question 9

how does decreased cardiac output lead to MI?

Answer 9

damage to heart wall makes the heart lose the ability to contract, the damaged area then bulges during systole, blood then pools in the bulge
(systolic stretch, ventricular aneurism)

Question 10

how does damning of the blood in Venus system lead to MI?

Answer 10

with the pumping ability lost, blood backs up
this leads to damage of the L side of the heart (pulmonary edema)
the renal compensation for this is aldosterone and ADH release

Question 11

how does ruptured infarct lead to MI?

Answer 11

the wall is thin and can rupture, blood then flows into the pericardial space (cardiac tamponade) which compromises function

Question 12

what are the 3 factors in ventricular fibrillation?

Answer 12

-increase K in the ECF
-increases sympathetic stimulation
-increased length of conduction pathway (nerve impulses take longer)

Question 13

what are the clinical manifestations of MI?

Answer 13

pain-chest, L arm, shoulder, neck, lower jaw, back
indigestion, nausea, vomiting, cool-clammy skin
increased cardiac enzymes
troponin
abnormal EKG

Question 14

what is the most diagnostic test of MI?

Answer 14

cardiac enzymes

Question 15

what re the cardiac enzymes?

Answer 15

phosphokinase, isoenzymes, CK-MB, lactate dehydrenase, and troponin

Question 16

when are troponin levels detectable of an MI?

Answer 16

4-6 hours after and stay elevated for 14 days

Question 17

what are the treatments fro MI?

Answer 17

pain relief-o2, B-blockers, vasodilators (nitroglycerin)