Heart failure Flashcards
What is the action of angiotensin converting enzyme? Where does this occur?
Converts angiotensin I to angiotensin II, which mainly occurs in the lungs
What neurohormonal adaptations occur to attempt to compensate for heart failure?
Increased sympathetic activity
Increases activation of RAAS
Initially beneficial, but chronically is maladaptive and causes further remodelling and worsening of heart failure
What three main things stimulate renin secretion?
Baroreceptors in afferent arteriole detect hypovolaemia
Increased sympathetic neural activity
Reduce chloride concentration in distal tubule detected by macular densa
What two main actions does angiotensin II have?
1) Arteriolar vasoconstriction
2) Reabsorption of sodium and water (both directly in proximal tubule, and indirectly by stimulating aldosterone secretion)
What three things stimulate aldosterone secretion? Which is the most potent?
Angiotensin II - most potent
ACTH
Serum potassium
What is the main action of aldosterone?
Increases sodium and water reabsorption in distal tubular by increasing expression of sodium channels
Increases potassium secretion
In heart failure, natriuretic peptides are released from (1) in response to (2). Compared to other neurohormonal responses, they are beneficial as they oppose (3) and cause (4). A drug targeting this is (5), which acts by (6).
(1) Atria and ventricles
(2) Stretch/increased intracardiac pressure
(3) Vasoconstriction
(4) Increased water and salt excretion
(5) Sacubitril (half of Entresto)
(6) Inhibiting neprolysin and thus preventing degradation of natriuretic peptides
Abnormalities in (1) function are mostly responsible for the HFpEF syndrome. This is often evidenced or exaggerated with (2).
(1) Diastolic
(2) Exertion
What are the diagnostic criteria for HFpEF?
Symptoms/signs of heart failure, with evidence of structural/functional cardiac abnormalities with LVEF >40% and raised BNP (NT-proBNP ≥125).
What is the most common cause of HFrEF?
Coronary artery disease
What are the diagnostic criteria for HFrEF?
Symptoms and signs of heart failure, and LVEF ≤40%
What are the three main goals of treatment for HFrEF?
1) Reduction in mortality
2) Prevention of recurrent hospitalisation
3) Improvement in symptoms, function, and QoL
What are the four cornerstone pharmacological treatments of HFrEF?
ACEi/ARNI
Beta blocker
Mineralocorticoid receptor antagonist
SGLT2 inhibitor
What did the PARADIGM-HF trial show?
Entresto superior to enalapril for outcomes of HF hospitalisation, CV mortality, and all cause mortality
What are the main heart failure trials on SGLTi, and what were the outcomes?
DAPA-HF (dapagliflozin) and EMPEROR-reduced (empagliflozin) showed a ~25% reduction in hospitalisation and cardiovascular death for those with HFrEF and LVEF ≤40 despite OMT, regardless of diabetes diagnosis.
What are the indications for ivabradine in HFrEF? What is its mechanism of action?
If symptomatic with LVEF <35% despite OMT, and sinus HR ≥70.
Ivabradine is a If (funny current) channel inhibitor > slows heart rate by slowing depolarisation.
When should an ICD be considered for patients with HFrEF?
NYHA class II-III, LVEF ≤35% despite 3 months of OMT, with ischaemic aetiology
When should CRT be considered for patients with HFrEF?
If LVEF ≤35% despite OMT, and QRS ≥150msec in sinus rhythm (consider if ≥130msec, especially if LBBB).
What non-pharmacological management should be suggested for all symptomatic patients with heart failure to improve aerobic capacity/exercise tolerance?
Exercise training/cardiac rehabilitation
