2E Flashcards
What two major variables affect the blood flow thru arteries?
pressure and resistance. Q(flow)=^P/R
What is the major influence on resistance?
Radius of the artery
What does vasodilation do to resistance and flow?
Decreases resistance and increases flow
What does vasoconstriction do to resistance and flow?
Increases resistance and decreases flow
Where is the entire blood supply to the myocardium derived from?
R & L coronary arteries
How much of the resting cardiac output does the heart receive?
5%
What two branches come off of the RCA?
Right Marginal and Posterior Descending
What two branches come off of the LCA?
Circumflex and Left Anterior Descending
Which is longer the RCA or the LCA?
RCA
How many main coronary branches are there?
6 big coronary branches
What is the main force that drives blood thru the coronary vessels?
Aortic pressure
What does the dichrotic notch help to facilitate?
Coronary blood flow (CBF)
Changes in what cause major changes in CBF?
Coronary resistance
What are the two types of normal factors that influence coronary resistance?
Neural and metabolic (adenosine, O2, CO2, K+, H+)
What is ischemia?
poor blood flow
Ischemic Heart Disease (IHD) is due to in imbalance in what?
Imbalance between supply and demand of oxygen, ie demand > suppy
What are the three main factors in the physiology of decreased blood supply?
Hemodynamic - increased resistance in coronary arteries or hypotension
Cardiac - valve disease or increased heart rate
Hematologic - anemias and poisons
What are the three major factors of the physiology of increased demand?
Myocardial hypertrophy
Overcoming excessive preload
Overcoming excessive afterload
What is the cause of IHD in most cases?
Atherosclerotic narrowing of the coronary arteries
The frequency of IHD is increased in patients who manifest which syndrome?
Metabolic syndrome
What is Angina Pectoris?
episodic chest pain caused by inadequate oxygenation of the myocardium
What is classic angina?
atheresclerotic disease that produces fixed obstruction of the coronary arteries - when metabolic needs of myocardium exceed the ability of the occluded coronary arteries to deliver adequate blood flow
What is variant angina caused by?
spasms of the coronary arteries - in most cases it is present along with coronary artery stenosis
What is the major difference of classic and variant angina?
Classic angina occurs with exertion or stress. Variant angina occurs during rest, with minimal exercise or nocturnally
What is unstable angina?
a clinical syndrome of myocardial ischemia that falls between stable angina and MI.
What is the difference b/w classic angina and unstable angina?
Classic angina is caused by a fixed obstruction and unstable angina is caused by atherosclerotic plaque disruption
Why is unstable angina also referred to as pre-infarction angina?
As the plaques are disrupted they cause a tiny hemorrhage that begins to form a clot and can completely occlude the blood vessel and cause an MI
What are the two distinct patterns of myocardial ischemic necrosis?
Transmural and subendocardial infarction
What is transmural infarction?
It traverses the entire ventricular wall from the endocardium to the epicardium
What is subendocardial infarction?
Limited to the interior one-third of the wall of the ventricle
What is the most common cause of death in the first several hours following infarction?
Arrhythmia
What can myocardial failure lead to?
congestive heart failure and/or shock
What is myocardial rupture?
a catastrophic complication of MI that usually occurs within the first 4-7 days and may result in death from cardiac temponade
What is cardiac tamponade?
compression of the heart by hemorrhage into the pericardial space
What is mural thrombosis?
A thrombus (clot) formation on the endocardium overlying the infarct
What is PTCA (percutaneous transluminal coronary angioplasty)?
A revascularization technique that sends a deflated balloon on a catheter to the blockage site and then inflates the balloon to crush the blockage
What is CABG (coronary artery bypass grafting)?
A bypass graft from the aortic arch to one of the coronary arteries beyond the blockage
What is the etiology of heart failure?
Anything that “taxes” the heart to the point where cardiac output (CO) is consistently decreased.
What is pressure overload caused by?
Pulmonary hypertension (RV) and systemic hypertension (LV)
What is volume overload caused by?
Valvular insuffiency
What can cause decreased cardiac contractility?
Cardiomyopathies and myocarditis
What can cause diminished filling?
pericarditis and cardiac tamponade
What is the result of LV heart failure?
Dyspnea (labored breathing) and orthopnea (shortness of breath) as a result of pulmonary congestion/edema. can lead to cyanosis
What is the result of RV heart failure?
Systemic edema and systemic venous distention that could lead to hepatomegaly, splenomegaly, ascites, peripheral edema, and jugular vein distention
