Heart failure Flashcards
(19 cards)
Causes of volume overload
L - R shunt
Valvular regurgitation
CHD
AV malformation 0 vein of Galen/hemangioma
Cardiac arrythmias
congenital compelte block
SVT
VT
Pressure Overload
L heart obstruction
- coarctation
- aortic stenosis
- hypoplastic left heart
Acute HTN: HUS, glomerulonephritis
R heart obstruction: pulm stenosis
Causes of ventricular dysfunction
Myocarditis
cardiomyopathy - dilated/hypertrophic/restrictive
sepsis
anaemia
pericardial effusion/tamponade
ischaemia
how does angiotensin 2 compensate in HF
- potent vasoconstrictor to incerase BP
- stim NA release from SNS
- promotes release of aldosterone
how does aldosterone 2compensate in HF
- increases Na ans H20 resorption and K secretion
- increases circ blood vol - increases centreal venous p (preload)
however causes peripheral oedema
how does ADH compensate in HF
Increase H20 absorption and decreases UO to increase total blood vol (preload and afterload)
how does endothelin compensate in HF
potent vasoconstrictor from vascular endothelial cells
promotes Na retention
endothelin 1 can be used as a prognostic factor for HF
function of diuretics
furosemide, spironalactone
increase excreition of Na and H20
decrease vol in circulation (preload)
function of ACEi
prevent conversion of Ag1 to Ag2, this increases plasma renin levels and decreases aldosterone
acts as systemic vasodilator decreases systemic vascular resistance , this decreases afterload
function of aldosterone antagonist - spironalactone
competes with aldosterone receptor sites in distal renal tubule
H20 excretion whilst retaining Na and K
function of beta blockers
increase stroke volue
decrease contractility and ventricular size
function of phosphodiesterase 3 inhibitor e.g. milrinone
positive inotrope
vasodilator without chronotropic effect (NO increases HR)
function of cardiac glycoside - digoxin
inhibits Na/K ATPase - increase intracellular Na and Ca
this increases force of contraction and decrease firing of AP
function of catecholamines - dopamine
stimulate b1, a1 and dopaminergic R
affects vasodilation, increases HR and contractiliy and can icnrease systemic vascular resistance
function of dobutamine - sympathomimetic
stronger B action than alpha
increase contractility and systemic vasodilation
function of alpha agonist - adrenaline
increases peripheral vascular resistance - alpha
positive chronotrope and inotrope - B2
Factors decreasing HR
PNS stimulation
digoxin
increase potassium
hypoxia
Na and Ca channel blockers
hypohtermia
Beta blockers
muscarinic receptopr agonist
Factors increasing HR
SNS stimulation
muscarinic antagonist
beta adrenoceptor agonist
circulating catecholamines
hyperhtyroidism
hyperthermia
decreases potassium
