Heart Failure Flashcards
What is the ejection fraction for HFrEF?
LVEF ≤40%
What is heart failure?
Inability of the ventricle to fill with or eject blood due to structural / functional cardiac disorders = reduced cardiac output (CO)
What is characteristic of HFrEF?
Dilated ventricle
Causes of HFrEF?
- chronic coronary disease (causing IHD)
- HTN
- obesity
- myocarditis
- tachycardia
What is the ejection fraction for HFpEF?
LVEF ≥50%
What is characteristic of HFpEF?
- impaired ventricular relaxation and filling
- normal wall motion
Symptoms of HF?
- fatigue, exercise intolerance
- fluid overload: peripheral edema, dyspnea (pulmonary edema)
Mechanism of symptoms of HF?
- fatigue & exercise intolerance: insufficient CO
- fluid overload: back pressure effects (blood backs up -> increase pressure in artery -> fluid moves from blood vessels into interstitial space -> edema)
Most common cause of HFpEF?
HTN
What are the NYHA classes of HF?
- I: asymptomatic HF, no limitations in physical activity caused by HF sx
- II: slight limitation of physical activity; asymptomatic at rest, but HF sx with normal level of activity
- III: marked limitations in physical activity because of HF sx; asymptomatic at rest
- IV: HF sx at rest or unable to carry out any physical activity
In HF, what is the SHORT-term compensation to maintain CO?
- increase HR & contractility: maintain CO
- vasoconstriction of arteries: maintain BP & CO
In HF, what is the LONG-term compensation to maintain CO and what opposes it?
Maintain:
- RAAS reabsorption of Na & water by kidneys: increase intravascular vol & load heart with more blood
Opposing:
- natriuretic peptide system: oppose effects of RAAS & SNS -> increase Na (& water) excretion, vasorelaxation, anti-hypertrophic, anti-fibrotic effects in heart
What is the main compensatory process called in HF to maintain CO?
Neurohormonal activation due to activation of sympathetic system
Cardiac remodelling & ventricular hypertrophy
How to calculate ejection fraction? (%)
(amt of blood pumped out of ventricle) / (total amt of blood in ventricle after diastole)
Sign of venous overload?
increase jugular vein pressure (enlarged & distended vein in neck)
How does orthopnea happen?
Pt lies down -> remove effect of gravity that causes blood to pool in leg veins -> blood returns to LV -> LV cannot handle increase vol of blood -> back pressure effects in lungs -> dyspnea when lying down
How does paroxysmal nocturnal dyspnea happen?
Pt goes to sleep -> loses sympathetic compensation -> heart beats slower & less hard -> fluid accumulates in lungs due to redistribution of blood pooled in legs to lungs & back pressure -> pt wakes up & becomes breathless
Difference between systolic and diastolic failure?
- systolic: affect ventricles
- diastolic: affect atriums
Where can back pressure effects occur?
Lungs, liver & spleen, legs (ankles)
What is BNP and when are they produced?
B-type natriuretic peptide, produced only by ventricles when they are stretched (due to fluid load aka HF)
What are the fantastic four for pharm treatment of HF?
- ARNi > ACEi > ARB
- BB (bisoprolol, carvedilol, metoprolol)
- MRA (spironolactone, eplerenone, finerenone)
- SGLT2i (Dapagliflozin / empagliflozin)
+ loop diuretic for congestion (frusemide)
+ ivabradine (adjunct to BB if symptomatic with HR ≥70 bpm)
Can you switch from ACEi to ARNi directly?
Cannot, must wash out period of 36h before starting ARNi
What does ARNi stand for? Example?
angiotensin receptor neprilysin inhibitor
sacubitril/valsartan
MOA of MRA?
Inhibit aldosterone -> prevent reabsorption of Na and hence water -> prevent water retention
Why will SCr increase slightly when ACEi are initiated?
Due to renal efferent artery dilation -> slightly decreased GFR
MOA of ARNi?
- sacubitril: prodrug metabolised to active metabolite that inhibits neprilysin -> increase levels of natriuretic peptides
- valsartan: ARB
When can BB be started?
When HF sx are stable & pt is euvolemic (not in fluid overload) otherwise acute decompensated HF
At what eGFR is MRA CI? At what eGFR does dose adjustment need to be done?
CI: eGFR <30
Dose adj: <50
MRA SE?
- hormonal SE (less with eplerenone): gynaecomastia, hirsutism, menstrual irregularities
- GI SE
- hyperK, hypoNa
At what eGFR are the SGLT2is CI?
- Dapagliflozin: eGFR <25
- Empagliflozin: eGFR <20
Doses of both SGLT2is?
10mg OD
When can SGLT2i be started?
When pts are euvolemic
SGLT2i SE?
- euglycaemic ketoacidosis (DKA)
- genitourinary tract infections
- diuretic effect: dehydration, hypotension, hypoglycaemia, renal impairment
Sick day advice for SGLT2i?
If sick (can affect glucose levels & cause vol depletion) with V/D, inability to drink/eat → stop SGLT2i → resume 24-48h after recovery (when eating & drinking normally)
When to hold off SGLT2i for surgery?
- elective: hold off 2 days before surgery (including day of surgery so total 3 days)
- for bowel prep: hold off 2 days before procedure (including day of procedure)
- for fasting procedures: hold off on the morning of procedure
Diuretics MOA?
Inhibit Na (& water) reabsorption
SE of loop diuretic?
- photosensitivity
- hyperuricaemia
- increase urination
- electrolyte disturbances: hypoK, hypoNa, hypoCa, hypoMg
Ivabradine MOA?
Reduce HR by inhibiting If current in SA node
Ivabradine SE?
- phosphenes (experience of seeing light w/o light actually entering eye)
- HA
- dizzy
- AF
Meds that worsen HF?
- -ve inotropic effects: non-DHP CCB, itraconazole, class I & III anti arrhythmic agents
- water & sodium retention: NSAIDs, corticosteroids, thiazolidinediones, minoxidil
- Proarrhythmic effects: cilostazol, stimulants
Non-pharm for HF?
- fluid restriction (use bottle to gauge)
- reduce Na intake, salt substitution
- K replacement (due to diuretics, ACEi/ARB, MRA)
- body weight monitoring (same time every morning, after toilet before breakfast): 2-3kg overnight
