24 HF Basics

Pathogenesis

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• pump draining water from tank being filled with water from pipe

• if pump is working, pumping water out, level of water in tank should be low

• pump starts to fail, less water out

• water level rises

• pump really failed

• tank completely filled, overflow

• pump = heart

• tank = lungs/veins

• water = blood

• chambers fail, blood left behind

• blood exert pressure on wall of heart chamber

• LV systolic pressure can be low in some heart failure

• LVEDP: always high, hallmark of LHF

• top arrow: peak, systolic pressure, may be high or low

• bottom arrow: diastolic pressure, always high

• systolic HF: less blood pumped out, more left behind

• diastolic HF: stiff ventricle, higher pressure

• closes MV at earlier point in time before LA empties, rise in LA pressure, LA begins to fail

• then, pulmonary capillary pressure rises, classic symptoms

• pulmonary capillary, Pc, hydrostatic pressure drives water out into interstitium

• LA pressure = 5, pulmonary capillary pressure also 5

• if LA P increase to 20 in heart failure, hydrostatic pressure in lung also becomes 20

• increase driving force to push fluid out = pulmonary edema

• domino effect: LV failure leads to high pressure in venous system, JVD and edema

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• CO falls, vasoconstrict to maintain perfusion and BP via Ang II and sympathetic

• ECV still down even with high TBW

• not enough to overcome RAAS

• One in a million: milrinone

• Don't phoster disinterest: milrinone inhibits phosphodiesterase

• CAMPaign: milrinone decreases breakdown of cAMP

• Flexing arm: milrinone increases cardiac contractility

• Dilated red donkey ears: milrinone causes arteriolar dilation and decreased afterload. Hypotension SE

• Turn the tide: nesiritide

• BuMP: nesiritide is a synthetic form of brain natriuretic peptide (BNP)

• GruMP: nesiritide increases cGMP in smooth muscle

• Dilated red ears and blue legs: nesiritide causes arteriolar and venous dilation, reducing afterload and preload

• Salty peanut stream: nesiritide causes natriuresis

Symptoms

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• sudden wakening in middle of night feeling SOB

• insomnia and sleeping upright with pillows behind

• backward failure: symptoms of blood backing up before ventricles, not symptoms from inability to push blood forward

• RHF in isolation: high pressure only in pulmonary artery, etc.

• cor pulmonale: isolated RHF, normal LH

• forward failure: symptoms when LV not pumping blood forward

• loss of appetite: poor perfusion to gut, weight loss (cardiac cachexia)

• confusion: poor perfusion to brain

• narrow pulse pressure: systolic pressure low

• can have clear CXR in chronic state

• RBC pushed out of capillaries, engulfed by macrophages in lung

• find height of bounce, add 5 to it

• Normal = 6 = 1 + 5

• press on abdomen just below liver

• leaves pit behind

Heart Sounds

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• S3 in question: left heart failing, pressure high in LA

• S4: more often in diastolic HF

Diagnosis

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• definitive: heart catheter