Heart Failure Flashcards
What are the NYHA classes?
- Class 1: no limitations of physical activity, no symptoms of CHF
- Class 2: Slight limitations of moderate or prolonged physical activity, comfortable at rest
- Class 3: Marked limitations of physical activity, comfortable at rest
- Class 4: confined to bed, discomfort during any form of physical activity, symptoms at rest
Contraindicated medications in heart failure
- NSAIDs: Worsen renal perfusion, reduce the effect of diuretics, may trigger acute cardiac decompensation
- Calcium Channel Blockers (verapamil, diltiazem): negative inotropic effect, worsen symptoms and prognosis - combination with B blockers is contraindicated
In heart failure, which are the medications that improve prognosis vs improve symptoms
Prognosis:
(a) Aldosterone antagonists - spironolactone, eplerenone
(b) B blockers - bisoprolol, nebivolol, carvedilol, metoprolol XR
(c) ACEi
Symptoms
(a) Diuretics
(b) Digoxin
Note:
- metoprolol, nebivolol and bisoprolol are B1 cardioselective
- carvedilol is non=selective beta blocker with additional a-blocking action
Side effects of ACE inhibitors
CATCHH
- Cough secondary to increased bradykinin
- Angioedema due to increase bradykinin
- Teratogen
- Increased creatinine/reduce GFR
- Hyperkalaemia
- Hypotension
- Used with caution in bilateral renal artery stenosis because ACEi will further ↓ GFR causing renal failure
Digoxin
- Used in patients with concomitant AF + heart failure (symptomatic LV systolic dysfunction) or remains symptomatic despite other therapy
- No mortality benefit
- Enhances contractility, reduces cardiac enlargement, improves symptoms, slows AV node
- Mechanism of Action: A cardiac glycoside that inhibits Na+/K+- ATPases in cardiomyocytes.-
Digoxin and half life
- Aim trough concentration 0.5-0.8 micrograms/L, avoid levels >1.2 micrograms/L to minimise risk of toxicity
- In patients with normal kidney fx, the half-life of digoxin is at least 24 hours
- Following initiation/change in digoxin dose, it takes at least 5 days (five half-lives) to achieve a steady state (when the concentration of the drug stays consistent)
Digoxin toxicity
• Cardiac
- ST depression with ‘reverse tick’
- Bradyarrhythmias – slow AF, 2nd-3rd degree AV block
- Junctional and atrial tachycardia
- VT –> VF –> asystole
• GI: nausea, vomiting, abdominal pain, diarrhea
• Visual: blurred vision, yellow/green discolouration, haloes
• CVS: palpitations, syncope, dyspnoea
• CNS: confusion, dizziness, delirium, fatigue
• Hyperkalaemia
Entresto
- Entresto (sacubitril + valsartan) - ARB + angiotensin receptor neprolysin inhibitor (ARN)
- Used in patients with persistent HFrEF (<35%)
Add to therapy if NYHA II-IV and LVEF <40% after 3-6 months of optimal therapy - ACEi must be stopped at least 36 hours before starting entresto
- Monitor hypotension, kidney impairment, hyperkalaemia
- Sacubitril: pro drug, further metabolised to the neprilysing inhibitor
What does neprilysin normally degrade?
Neprylisin is a neutral endopeptidase which normally degrades severe endogenous vasoactive peptides including natriuretic peptides, bradykinin and adrenomedullin, angiotensin II
What does neprilysin normally degrade?
Neprylisin is a neutral endopeptidase which normally degrades severe endogenous vasoactive peptides including natriuretic peptides, bradykinin and adrenomedullin
Ivabradine
- Indication
- MOA
- SE
INDICATIONS in HF (SHIFT Trial)
- LVEF ≤ 35%
- Sinus, HR ≥ 70-75
- On stable background HF therapy including beta blockers if tolerated
- One hospitalisation for HF ≤ 12 months
MOA
- direct sinus node inhibitor, selectively inhibits the If channel (funny ion channels) in the pacemaker cells of the SA node → prolongs slow depolarisation (phase 4) → slows heat rate which in turn lowers cardiac workload and myocardial oxygen demand
SE
- Visual changes
- Bradycardia
- AF
- HTN
Indications for implantable cardiac defibrillator (ICD)
Primary Prophylaxis
- CHF with EF <35% and >1 month after MI or >3 months after CABG
- EF < 35% and HF NYHA I-III
Secondary Prophylaxis
- History of sudden cardiac arrest, VF
Indications for cardiac resynchronisation therapy
Dyssynchronous myocardial contraction evidenced by broad QRS
- CHF with EF < 35%
- QRS >120ms, broad complex, LBBB
- NHYA II-IV
- Sinus rhythm
- Optimal medical therapy for at least 3 months
Why should iron be corrected in heart failure?
To improve symptoms and quality of life and reduce admissions
no mortality benefit
Cardiac transplantation indications
- End stage CHF (NYHA IV)
- EF < 20%
- No other viable treatment options
Eligibility
- Smoking cessation
- BMI (weight < 100)
- Nil malignancy
- Compliance with treatment