Study sets, textbooks, questions
Upgrade to remove ads
Phys: Chapter 22: Cardiac Failure
Terms in this set (41)
what is common among all causes of heart failure?
decreases ability of the heart to pump
what are the two results of decreased pumping of the heart
1) decreased cardiac output
2) damming of the blood in the veins, causing increased venous pressure
during heart failure, what increases as cardiac output falls?
right atrial pressure due to increased volume overload and venous return
what is the best known reflex to a large drop in Cardiac output? what does it respond to
diminished arterial pressure
other than increasing force of contraction, what do sympathetics do to the heart?
increase tone of vessels, nameably veins, raising mean systemic filling pressure 100% (12 to 14mm Hg)
a man is having a heart attack and feels like fainting, how long till sympathetics kick in?
after sympathetics kick in post-MI, what happens as a cause of low CO?
fluid retention by kidneys
cardiac output below____% results in anuria
what is the effect of fluid retention increasing mean systemic filling pressure?
increase the pressure gradient for causing venous flow of blood toward the heart
what is the effect of distending veins via fluid retention?
reduces venous resistance and allows ease of flow of blood to the heart
describe the dark side of fluid retention post MI
If the perfusion of the kidneys dropped too low the kidneys may become damaged. If this is the case, they will not stop retaining fluid and when the heart is pumping at its max again, this fluid adds more volume, that the now damaged heart must push against.
what are the 4 effects of excess fluid retention on a damaged heart?
fluid in lungs> pulmonary edema> decreased oxygenation
how does the myocardium recover post MI?
hypertrophy of remaining myocaridum
your patient had a heart attack one month ago. is his heart as healed as it can be?
full healing in 5-7 weeks
However, rapid recovery occurs during the first few days and weeks
how do you expect a patient to appear a few days after MI?
(all from sympathetics)
what is decreased in compensation heart failure? hint: this is why you don't want them to exercise
cardiac reserve (If you look at point D, it can't increase its cardiac output as much as it could have with a normal heart)
what is decompensation heart failure? what is the cause?
Heart can't pump enough blood to excrete enough fluids from the kidneys.
increase in edematous state due to increased heart failure
kidneys don't recieve adequate bloodflow to excrete fluids
critical cardiac output level to maintain proper perfusion of the kidneys for fluid balance
what happens when the heart cannot reach the critical cardiac output required for the kidneys to function properly (3)? what is this called?
decompensation heart failure
-progressive retention of fluid
-progressive elevation of filling pressure
-progressive elevation of right atrial pressure
what would you see in a patient with decompensation heart failure upon clinical exam?
dyspnea, bubbling rales, and edema of lungs
(all from edema of lungs)
how would you treat decompensation heart failure?
cardiotonic drug such as digitalis to increase Cardiac output (digitalis)
diuretic to balance fluids
what effect do cardiotonic drugs have on a healthy heart?
increase strength of failing myocardium 50-100%
How does digitalis increase the calcium ions in muscle fibers, strengthening heart contractions?
inhibits Na/K ATPase
more Na in cell means less activity of Na/Ca exchanger leaving more Ca in the cell
what do you expect to see with left sided heart failure (2)?
pulmonary vascular congestion
(death by suffocation)
What is the term for circulatory shock syndrome caused by inadequate cardiac pumping?
cardiogenic shock aka cardiac shock
describe the vicious cycle of cardiogenic shock
inadequate blood flow decreases coronary perfusion which further decreases ability to pump and again decreases blood flow
how would you treat a patient in cardiogenic shock? what are your chances of success?
digitalis to increase cardiac ouput
infusion of whole blood or plasma (raise the BP)
unblock clot (catheter/ streptokinase/ tPA)
true or false? acute heart failure causes immediate development of peripheral edema
causes a drop in capillary pressure, not rise
4 causes of reduced renal output of urine during cardiac failure
decreased glomerular filtration rate
activation of RAAS and increased reabsorption of water and salt
activation of sympathetics
other than decreased arterial pressure, how does heart failure cause decreased glomerular filtration rate?
sympathetic constriction of afferent arterioles
excess ____ is one of the most powerful known stimuli for aldosterone secretion and rises in response to cardiac failure
4 effects of the sympathetic nervous system on the kidneys
1-constrict renal afferent arterioles
2- reabsorb salt and water by alpha-adrenergic receptors on tubular epithelial cells
3- stimulate renin and A II release
4- stimulate ADH
what is atrial natriuretic peptide
released in response to atrial stretch and prompts excretion of salt and water
what are some heroic therapeutic measures that can be used in a patient with acute pulmonary edema?
tourniquets on extremities to decrease workload of heart
rapid acting diuretic
cardiotonic drug - digitalis
normal cardiac reserve
Cardiac Reserve of heart failure?
Heart failure: 0%
how to test cardiac reserve
What are three effects of the exercise test for those who have low cardiac reserve?
2. Extreme Muscle Fatigue
3. Excessive Increase in HR
Flip over to the other slide before reading these answers
A: Normal Venous Return
B: Autonomic Compensation
C: Continued fluid retention by kidneys
What does point A on the graph represent?
Point C and on?
well known theapeutic effect of digitalis
diuresis- increased cardiac output enough to properly perfuse the kidneys and allow proper fluid balance
what effect does an arteriovenous fistula have on the heart? what is it?
overloads the heart because of excessive venous return, not because of decreased pumping capability
-direct opening between a large artery and a large vein
what effect does beriberi have on the heart? what is it?
overloads because of excessive venous return by decreasing vascular resistance and also by depressing pumping capacity of the heart
-avitaminosis (thiamine) deficiency
Other sets by this creator
Medical Jurisprudence Part 2
Medical Jurisprudence Part 1
Micro 12: Streptococci and Enterococci:…
Biochemistry Unit 2