Heart Failure Flashcards
Heart failure caused by any condition that does what?
↓ efficiency of myocardium thru damage or overloading
Physiological definition of HF
heart unable to pump at required rate for metabolizing tissues OR has to use elevated filling pressure to do so
Clinical definition of HF
abnormalities of L vent fxn and neuorhormal regulation accompanied by:
effort intolerance
fluid retention
reduced longevity
Goal of cardiovascular system is?
maintain CO
Consequences of ↓ CO? (2)
hypoperfusion of organs
exercise intolerance
Consequences of left failure?
↑ L atrial pressure ->
pulmonary congestion and dyspnea
Consequences of right failure?
↑ R atrial pressure ->
systemic congestion
LE edema
Life expectancy w/ L vent failure?
5 yrs
HTN causes what kind of overload?
pressure overload
Valvular disease causes what kind of overload?
pressure and volume overload
MI causes what kind of dysfxn?
regional
Cardiac dyfxn characterized by? (4)
↑heart size and mass
adnorm proteins
fibrosis
inadequate vasculature
Depression of contractility leads to?
↓ length-tension curve:
ejection of ↓ SV at same EDV
Symp NS compensation for ↓ contractility?
can stim ↑ contractility but not back to normal levels,
eventually SNS is exhausted
Symp NS becomes depressed when what happens (3)?
1) ↓ cardiac NE stores
2) ↓ β-adrenoceptor denisty
3) ↓ catecholamine sensitivity
Physio basis for ↓ contractility? (3)
1) impaired Ca2+-induced Ca2+ release
2) fiber-type changes
3) ↓ Ca2+ sensitivity
Kidney tries to compensate for ↓ CO how?
retains H2O to cause ↑ in blood volume ->
↑ EDV
Final signs of HF: contractility?
contractility significantly decreased, SNS no longer able to compensate
Final signs of HF: SV?
no longer able to maintain SV
Final signs of HF: stretch?
mm fibers stretched beyond optimal length
Final signs of HF: EDV?
increased EDV no longer effective
Forward failure caused by?
inadequate SV
Backward failure caused by?
blood back-up in venous system ->
congestive HF
Eccentric hypertrophy is?
↑ mm mass where vent gets longer/bigger, not thicker (adds sarcomeres)
Eccentric hypertrophy caused by?
volume overload:
vents dilate ->
regurg and ↑ diastolic P ->
↑ mm mass
Concentric hypertrophy is?
↑ mm mass where walls get thicker (∆ in ratio of contractile proteins to mitochondria)
results in smaller chambers
Concentric hypertrophy caused by?
pressure overload:
chronic SNS stim ->
↑ contractility ->
SNS exhaustion
1st step in L vent failure?
L vent weakens -> ↓ emptying
2nd step in L vent failure?
↓ CO to system
3rd step in L vent failure?
↓ renal blood flow ->
stim renin-angiotension/aldosterone secretion (fluid retention)
this is postive-feedback loop
4th step in L vent failure?
blood back-up in pulmonary vein ->
↑ P in pulmonary capillaries
5th step L vent failure?
↑ P in pulmonary capillaries ->
pulmonary congestion/edema
High pulmonary arterial pressure from L vent failure can lead to what effect on R heart?
↑ afterload in R vent
Ѧ R vent failure
L vent failure causes edema where?
pulmonary
Most common = CHF
R vent failure causes edema where?
peripheral
1st step R vent failure?
R vent weakens -> ↓ emptying
2nd step R vent failure?
↓ CO to system
3rd step R vent failure?
↓ renal blood flow ->
stim renin-angiotension/aldosterone secretion (fluid retention)
4th step R vent failure?
blood back-up in systemic circ (vena cava) ->
↑ venous P ->
↑ capillary P
5th step R vent failure?
↑ capillary P ->
edema in LE, liver, abdominal organs
6th step R vent failure?
venous P now extremely ↑ ->
distended neck vein and cerebral edema
Shock is result of what?
failure of CVS to adequately perfuse tissues ->
impaired oxygenation and cell metabolism
Shock progresses to?
hypotension, organ failure and death
Cardiogenic shock is result of?
↓ myocardial fxn
Hypovolemic/hemorrhagic shock is result of?
↓ blood volume
bleeding, diarrhea, vomiting, burns
Vasogenic (vessel produced) shock is result of?
vasodilation from:
1) anaphylactic rxn (peripheral vasodi)
2) septic (massive vasodi)
Neurogenic shock is result of?
inhibited symp vasoconstrictor nerves ->
loss of vascular tone
Common final event of all types of shock is?
hypoxia
Hemorrhagic Shock specifically due to?
fall in arterial pressure (MAP) from massive blood loss
Compensatory response to Hemorrhagic Shock?
Baroreceptor reflex -> ↑ SNS:
↑ HR, contractility, TPR, venoconstriction, shunting blood from skin to organs
RAS:
↑ angiotensin II and aldosterone
ADH release
Result of Irreversible Shock?
body can’t compensate ->
severe vasoconstriction of essential beds
(brain, heart, renal)
