KIN 407 Midterm 2 Flashcards
Acute coronary artery syndromes?
Stable angina pectoris, unstable agina, acute MI, sudden cardiac death
What determines myocardial oxygen supply?
O2 content from coronary blood flow…coronary perfusion pressure, coronary vascular resistance (external compression and intrinsic regulartion via neural innervation, endothleial factors, and local metabolites)
What determines myocardial oxygen demand?
Wall stress and heart rate and contractility
Situational triggers of coronary events?
Physical exertion, emotional excitement or anger, large meal, cold weather (vasoconstriction)…all constrict arteries or rupture plaque
Stenosis at 70% versus 90%?
70%, BF is adequate at rest but becomes a challenge with stress…stenosis at >90% is insufficient BF at rest
5 types of angina pectoris?
Stable angine, silent angina, variant angina, unstable angina, postprandial angina
What is stable angina?
chronic pattern of angina, narrow lumen, vasoconstriction, relieved by rest, NO PERMANENT DAMAGE
Variant angina?
pain at rest, coronary artery spasm, but if severe enough can cause sudden cardian death. “Prinzmental angina”
Silent angina?
No symptoms/pain, detected by EMG, diabetics, women and old people are most common, damage to microvasculature of heart
unstable angina?
Increased frequency and duration of angia, platelets –> thrombus, pain during less exertion or rest, high freqency of progression to an MI
Postprandial angia?q
After a meal, a marker of extensive CAD and can precipitate to an MI
Consequences of ischemia?
1) Swithch from aerobic to anaerobic metabolism because of inadequate O2 2) Impaired contraction (both systolic contraction and diastolic relaxation…both require O2) 3) Increased LV diastolic pressure –> pulmonary congestion (dyspnea) 4) Waste products (esp. H+) activate peripheral pain receptor in the C7-T4 causing angina and triggers arrhythmia 5) Increased SNS, leading to sweating, high HR and BP
Symptoms of angina?
Chest pain (pressure, discomfort, tightness, burning, heaviness. location is diffuse not localized). tachycadria, sweating, nasusea, fatigue and weakness. ECG changes
Diagnosis of ischemia/angina/
history, physical exam, ECG, stress testing, nuclear imaging studies, echocardiogram, coronary angiography
Treatment for ischemia?
restore O2 supply balance, pharmacology, revascularization, coronary bypass sutgery
What is an MI?
A myocardial infarction…death of tissues (myocardial necrosis)…prolonges cessation of blood supply…acute thrombus,,,depends on amount of occlusion and extent of collateral circulation…damage is IRREVERSBLE
SIgns of unstable angina?
ST depression, no tissue damage, partial occlusion, no necrosis of tissues, no TN-T or TN-I in blood
Signs of a non-St-elevation MI (NSTEMI)?
ST depression, damage, partial occlusion, necrosis of tissue, TN-I an TN-T in blood
ST-Elevation MI (STEMI)?
ST elevation, damage (most), complete occlusion, necrosis of tissues, TN-I and TN-T in blood
What is a transmural infarct?
Entire thickness of myocardium, and results from total prolonged occlusion
What is a subendothelial infarct?
Inner most layer of the myocardium…some contraction may still occur
Amount of tissue affected from a MI depends on?
Mass of affected myocardium, magnitude and duration of impaired flow, O2 demand at that region, collateral circulation (more collaterals = less damage), the degree of tissue response that modifies the ischemic response
Metabolic changes occur hoe long after blood flow decreases?
Decrease function in 2 minutes
When does irreversible cell injury occur?
20 minutes