10. Heart Failure Flashcards
Define heart failure.
A complex clinical syndrome of signs and symptoms that suggest the efficiency of the heart as a pump is impaired.
The heart is unable to deliver blood at a rate that meets the metabolic demands.
What are the 2 broad categories of heart failure?
- Systolic failure: the ability of the heart to pump blood around the body is impaired.
- Diastolic failure: the heart is pumping blood effectively but is relaxing and filling abnormally.
What is the difference between systolic and diastolic failure?
Systolic = impaired left ventricular contraction
Diastolic = impaired left ventricular relaxation
Give the major types of heart failure.
Systolic/diastolic, low output/high output, left/right
Name the different classifications of HF.
Briefly describe the pathophysiology of heart failure.
When the heart fails, compensatory mechanisms attempt to maintain CO. As HF progresses, these mechanisms are exhausted and become pathophysiological.
What is the most common cause of heart failure?
Ischaemic heart disease.
Give 5 causes of heart failure.
- Commonest cause: IHD.
- Hypertension (pulmonary)
- Cardiomyopathy.
- Excessive alcohol.
- Obesity.
- Valvular disease (commonly aortic stenosis)
- Pericardial causes e.g. pericarditis, effusion
- Myocarditis
- Arrythmias (commonly AF)
Why are men more commonly effected by heart failure than women?
Women have ‘protective hormones’ meaning they are less at risk of developing heart failure.
What are the compensatory mechanisms in heart failure?
- Sympathetic system.
- RAAS.
- Natriuretic peptides.
- Ventricular dilation.
- Ventricular hypertrophy.
Explain how the sympathetic system is compensatory in heart failure and give one disadvantage of sympathetic activation.
The sympathetic system improves ventricular function by increasing HR and contractility = CO maintained.
BUT it also causes arteriolar constriction which increases after load and so myocardial work.
Explain how RAAS is compensatory in heart failure and give one disadvantage of RAAS activation.
Reduced CO leads to reduced renal perfusion; this activates RAAS. There is increased fluid retention and so increased preload.
BUT it also causes arteriolar constriction which increases after load and so myocardial work.
What is the counter regulatory system to RAAS?
ANP/BNP hormones.
What hormones does the heart produce?
ANP and BNP.
What are the functions of ANP and BNP?
- Increased renal excretion of Na+ and therefore water.
- Vasodilators.
- Inhibit aldosterone release.
What metabolises ANP and BNP?
NEP.
Why can NEP inhibitors work for heart failure treatment?
NEP metabolises ANP and BNP. NEP inhibitors can therefore increase levels of ANP and BNP in the serum.
Give 3 properties of natriuretic peptides that make them compensatory in heart failure.
- Diuretic.
- Hypotensive.
- Vasodilators.
Describe the ventricular remodelling seen in heart failure
Initial dilatation.
Hypertrophy, loss of myocytes, increased interstitial fibrosis.
Give the 4 cardinal signs of HF.
- Exertional dyspnea / SOBOE (breathlessness worsened by exertion)
- Orthopnoea
- Paroxysmal Nocturnal Dyspnoea
- Peripheral oedema (swollen ankles and swelling in the legs)
- Fatigue
- Cold peripheries
Give 2 signs of RHF.
- Raised JVP
- Basically, right-sided HF is to do with the vena cava + venous return - the blood can’t return back to the heart - so there’s a backlog/backflow - back down the veins - so causing oedema - Ascites.
- Hepatomegaly may be seen