Lecture 06 LV Dysfunction and HF 2 Flashcards
1. Describe the patterns of clinical presentation of LV dysfunction, chronic heart failure and acute heart failure 2. Describe neurohumoral activation in heart failure, with an understanding of the interaction between the renin-angiotensin-aldosterone and sympathetic nervous systems 3. Describe pharmacological interventions in chronic heart failure, with an emphasis on neurohumoral blockage rather than direct stimulation of cardiac contraction in patients with chronic heart failure 4. Understa
What advantages are there for the renin-angiotensin system?
works well for blood loss by conserving the central blood volume and pressure and shutting down useless areas of the body
What is a problem of the renin-angiotensin system?
system doesn’t work in cases of heart failure
can’t distinguish the different between heart failure and blood loss
How does the renin-angiotensin system work?
angiotensin + renin = angiotensin I
angiotensin I + ACE = angiotensin II
How does the sympathetic envois system impact on the renin-angiotensin system?
release of noradrenaline
increases renin levels therefore increasing angiotensin II
What effect does angiotensin II have on the body?
aldosterone release
increased peripheral resistance
increased cardiac output
What effect does aldosterone have on the body?
tubular sodium reabsorption
salt and water retention
How does the body respond to acute blood loss?
tachycardia
positive inotropic effect
vasoconstriction
sodium and water retention
How does the body respond to LVSD?
tachycardia positive inotropic effect (NA) vasoconstriction sodium and water retention chronic adrenergic stimulation
What treatments can be given to a patient with LVSD?
diuretics
vasodilators
aldosterone antagonists
ACE inhibitors
Give examples of ACE Inhibitors (x4)
enalapril
ramipril
perindorpril
trandolapril
What effect did Enalapril have on patient mortality?
31% reduction in mortality - significant
Why is Enalapril beneficial to hospitals?
significantly reduces hospitalisation from HF significantly reducing costs
What other conditions can ACE inhibitors be used for?
hypertension and diabetic nephropathy
What are the adverse effects of ACE inhibitors relating to decreased angiotensin II formation?
hypotension
acute renal failure
hyperkalaemia
teratogenic effects in pregnancy
What are the adverse effects of ACE inhibitors relating to increased kinin production?
cough
rash
anaphylactoid reactions
Why is there an increase in kinin production in response to ACE inhibitors?
angiotensin II is responsible for the breakdown of bradykinin
What three beta-blockers have been shown to be beneficial in treating heart failure?
carvedilol
bisprolol
metoprolol
What else can beta-blockers be used to treat?
IHD
angina
arrhythmia
hypertension
What are the adverse side effects of beta-blockers?
CNS - fatigue, headache, sleep disturbances, nightmares
vascular - bradycardia, hypotension, cold peripheries
erectile dysfunction
What conditions can beta-blockers make worse?
asthma or COPD
peripheral vascular diseases - claudication or Raynaud’s
heart failure (standard dosing)
How are beta-blockers prescribed to avoid worsening of heart failure?
initially prescribed very low dose and increase the amount slowly
What effect does Digoxin have on heart failure?
decreases hospitalisation but does’t decrease mortality
How does Ivabradine work?
blocks the sodium funny current in the sinus node slowing the firing rate
What is Ivabradine used to treat?
angina and heart failure
