Heart Failure Flashcards
Diastole:
relaxation and filling of the heart
Systole:
contracting and pumping out blood
Cardiac output (CO):
the amount of blood pumped out of the heart ((Ventricles) to the body per minute (normally ~3-5 liters)
CO = SV x HR, therefore CO can be increased as a result of increase SV/HR or both
Stroke volume (SV):
the amount of blood pumped out of the heart with each heartbeat (normally ~60-70ml)
Estimated SV = End diastolic Volume (EDV) - End systolic Volume (ESV)
EDV: the volume of blood in the ventricle when its full prior to contraction
ESV: the volume of residual blood left in the ventricle following contraction
Preload:
the volume of blood in ventricles at the end of diastole (EDV). Preload is determined by the amount of blood returned to the right side of the heart from the systemic circulation
Afterload:
resistance the left ventricle must overcome to circulate the blood. An increase in afterload will increase ESV (due to a decrease in SV and harder to eject the blood)
Inotropy:
force of ventricular contraction. Increase in sympathetic activity will increase contractility and thus SV - allows more complete ejection of blood so there will be a reduction in ESV. Inotropy also increases HR
Heart Rate (HR):
The number of beats per minute. Influenced by sympathetic input (can also be impacted by temperature and thyroxine levels)
ARNI
Sacubitril (Neprilysin Inhibitor) +
Valsartan (ARB)
MOA: Sacubitril inhibits neprilysin reducing degradation of natriuretic peptide. It also increases angiotensin 2 conc. which is blocked by valsartan. This combination produces vasodilation, increasing glomerular filtration rate, reducing sympathetic tone and aldosterone release and increases bradykinine level
Indication: HF (NYHA class 2-4) with HFrEF
Side effects: Hyperkalaemia, increased serum creatinine, renal impairment, hypotension
Counsel:
- Get up gradually as you may feel dizzy
- Do not take potassium supplement while your taking this medicine
- If changing from an ACEI or SARTAN ensure patients understand the changes and cease drug to avoid confusion
Dose: initially 24/26 mg bd if tolerated, double dose every 2-4 weeks to 97/103 mg bd
Do not use with an additional sartan
Souble cGMP stimulators
(Vericiguat)
MOA: Increase vasodilation through the activation of cGMP. This is by nitric oxide (promotes vasodilation) causing the production of cGMP interfering with the contractile medchanism within smooth muscle.
Indication: symptomatic HF with ef <45%
Side effect: hypotension, fainting, dizziness, anaemia, headache
Counsel
- Take with food
- If you feel dizzy ro light-headed while taking this medicine contact doctor
Selective Cardiac Myosin Activator
(Omecamtiv Mecarbil)
MOA: Targets and activates myocardial ATPase improving the cross bridge between myosin and acting filaments enhances cardiac contractility. Does not lead to CA accumulation
Indication: Usually seen in those with persistent LVEF <35%
Ferric Carboxymaltose
MOA: Improves ferritin levels for patient with HF that have iron deficiency (not they may or may not have anaemia). It is taken up by macrophages whereby iron is released and stored as ferritin or interacts with transferrin for transport
Indication: Considered if ferritin <100 or if ferritin 100-299 and transferrin saturation <20%
ACE inhibitors
Withhold loop diuretics for 24 hours on initiation of ACE inhibitors
Withhold/reduce dose of thiazide for 24 hours on initiation of ACE inhibitors (cause hypotension)
Start treatment when patient is supine to minimise hypotensive effect
Beta blockers
Start low and go slow
Potential deterioration symptoms of HF during initiationa dn titration of BB - dont stop taking this medication
Medications include: Bisoprolol Carvedilol, Metoprolol
Aldosterone Antagonist
Eplerenone: initially 25mg daily, increase to 50mg daily within 4wks if potassium conc <5mmol/L Metabolised by CYP3A4 (conc increased, increase SE when given with an Cyp3a4 inhibitor)
Spironolactone: Initially 25mg daily, increase to 50mg daily after 8 weeks if HF progressess and potassium conc <5mmol/L . Not suitable for CrCL<30ml/min
SGLT2 Inhibitor
Empagliflozin: 10mg once daily. not recommended if eGFR <20mL/min/1.73m2
Dapagliflozin 10mg once daily. not recommended if eGFR <25mL/min/1.73m2
Loop diuretics
Bumetanide: 0.5-4mg once or twice daily
Frusemide: initially 20-40mg once or twice daily
Take in the morning. If you are taking it twice a day take first dose in the morning and second dose at lunchtime
1mg of Bumetanide = 40mg frusemide
Digoxin
Used for those HF and AF or poor rate control
Toxicity may result deterioration renal function or dehydration
Ivabradine
Added to therapy if continuing symptoms of moderate to severe HF
Aim of resting heart rate of 50-60 beats/minute
CYP3A5 inhibitors may reduce ivabradines clearance and increase ADR
Start 5mg bd, adjust 2-4 weeks according to HR
