Left Ventricular Failure Flashcards
78 y.o. man had a large anterior MI 3 years ago. initially he made a good recovery although he has required to take a diuretic for ankle swelling since. in the last 2 months, he has become SOBOE. you suspect he has developed LVF.
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a) give 2 additional sx which would support his dx.
- breathing: exertional dyspnoea, orthopnoea, PND
- exercise: poor exercise tolerance, fatigue, weakness
- lungs: cardiac wheeze, nocturnal cough with pink frothy sputum
- other: impaired mental status, cold peripheries, syncope or presyncope
b) you arrange for a CXR. give 4 features which would support the dx of LVF?
ABCDE
- Alveolar oedema
- kerley B lines
- Cardiomegaly
- Dilated prominent upper lobe vessels
- pleural Effusion
c) give 2 neurohumeral mechanisms which may be activated in heart failure.
1) sympathetic NS activity
- fall in CO detected by baroreceptors ⇒ ↑catecholamines ⇒ ↑HR/BP
2) RAAS
- ↓renal perfusion activates RAAS → angiotensin II (↑PVR) and aldosterone (↑BV) ⇒ ↑BP
3) ADH
- ↓BP and angiotensin II trigger release ⇒ ↑resorption ⇒ ↑BV ⇒ ↑BP
4) Natriuretic peptides
- ANP and BNP released in response to ↑sympathetic stimulation, atrial distension and AG II
- both inhibit RAAS so ↓BV/BP making them beneficial
- however, they are not released in sufficient enough quantities to make a significant difference
d) when starting this pt on ACEi, give 3 precautions you would take?
1) warn about side effects e.g. 1st dose hypotension, cough, hyperkalaemia, renal impairment
2) start at low dose and titrate up
3) check U+Es before initiating rx (?hyperkalaemia, renal impairment)
4) check pt is not taking drugs that have interactions with ACEi e.g. ciclosporin (↑risk hyperK+)
e) define preload and afterload?
preload = cardiac muscle length prior to ventricular contraction dependent on end-diastolic volume
afterload = pressure against which the ventricle has to contract
f) what is Starling’s law?
the amount of blood ejected during systole is proportional to the amount of blood entering the ventricle during diastole due to the length-tension relationship within the ventricle
