CVS 11 (Heart Failure) Flashcards
Define Heart failure:
Chronic failure of heart to provide sufficient output to meet the body’s requirements, despite adequate filling pressure
List some causes of heart failure:
- Ischaemic heart disease (>70% cases)
- Hypertension
- Dilated cardiomyopathy (infection/drugs/pregnancy)
- Valvular heart disease
- Restrictive cardiomyopathy (ie Amyloidosis)
- Hypertrophic cardiomyopathy
- Pericardial disease
- Arrhythmias
Right sided heart failure rarely occurs without left sided heart failure, except…
If chronic lung disease present
How does left sided heart failure cause right sided heart failure?
- Pressure build up in pulmonary veins due to back-up of blood
= Pulmonary hypertension - Backs-up into right heart, overstretching the fibres causing right heart failure
What are the 2 types of myocyte hypertrophy?
1) Eccentric = Elongation in response to volume overload, causes thinning of heart wall
2) Concentric = Increase in width, in response to pressure overload, causing thickening of heart wall
What type of myocyte hypertrophy causes thinning of the heart wall?
Eccentric hypertrophy
What type of myocyte hypertrophy causes thickening of the heart wall?
Concentric hypertrophy
Heart failure stimulates an increased SNS innervation to the CVS. Explain how this can exacerbate symptoms:
- Increased vasoconstriction increases stress on the heart, causing myocardial hypertrophy
- Increased heart rate and contractility increases the O2 demand, resulting in decreased contractility
What is the result of Angiotensin II at AT2 receptors?
Increased NO production
= vasodilation
Name the most sensitive serum biomarker for heart failure:
BNP (Brain Natriuretic Peptide)
How do Natriuretic peptides help the body in heart failure?
Decrease blood pressure via:
- vaso and venodilation
- decrease RAAS stimulation = natriuresis + diuresis
Why is the release of ADH in heart failure ‘paradoxical’?
- ADH causes increase in blood pressure, which exacerbates and worsens heart failure
How is NO production affected in heart failure?
Increased NO production, to maintain tissue perfusion (oppose vasoconstriction caused by SNS and RAAS)
How does bradykinin help the body in heart failure?
- Natriuresis
- Vasodilation
- Increased prostaglandin production
= Decreased blood pressure
How does GFR change during heart failure progression?
Early HF
= Vasodilation due to prostaglandins and NO
= GFR maintained
Late HF
= Vasoconstriction due to SNS, RAAS, ET-1
= GFR falls
How does serum urea and creatinine change during heart failure progression? Why?
Increases in severe heart failure
- GFR falls due to SNS, RAAS and ET-1
How does concentric hypertrophy exacerbate heart failure?
Concentric hypertropy = thickening of wall, causing stiffness of heart, impairing contraction, decreasing cardiac output
What is the name given to describe ‘shortness of breath when lying flat’?
Orthopnoea
Symptom of heart failure
Define Orthopnoea:
Shortness of breath when lying flat
List some signs/symptoms of left heart failure:
- Fatigue
- Dyspnoea on exertion
- Orthopnoea
- Paroxysmal nocturnal dyspnoea
- Tachycardia
- Peripheral oedema
- Basal pulmonary crackles
What is Paroxysmal Nocturnal Dyspnoea?
Attacks of severe shortness of breath and coughing which usually occur at night
Symptom of left heart failure
Why do patients with LEFT-sided heart failure often get peripheral oedema?
Reduced CO
- reduced kidney perfusion = RAAS activation
- Aldosterone increases Na+ and H2O retention
- Increased fluid = increased venous pressure
- Increased capillary hydrostatic pressure
- Fluid moves out of vessels into interstitial fluid
= Peripheral oedema
How can you test for cardiomegaly during an examination?
Feel for apex beat - will be displaced/sustained
What heart sounds can be usually heard in left-sided heart failure?
- S3 or S4
- Mitral regurgitation murmur
List some causes of RIGHT-sided heart failure:
- Secondary to left-sided heart failure (most common)
- Chronic lung disease
- Pulmonary embolism
- Pulmonary hypertension
- Pulmonary/tricuspid valvular disease
- Left to right shunt (ASD/VSD)
- Isolated Right Ventricular Cardiomyopathy (idiopathic)
List some signs/symptoms of RIGHT-sided heart failure:
- Fatigue
- Dyspnoea
- Anorexia
- Nausea
- Increased JVP
- Tender, smooth hepatic enlargement
- Peripheral pitting oedema
- Ascites
- Pleural effusion
Why do patients with RIGHT-sided heart failure often get peripheral oedema?
Increased RH pressure
- Increased systemic venous pressure
- Increased capillary hydrostatic pressure
- Fluid moves out of vessels into interstitium
= Peripheral oedema
Define cor pulmonale:
Right-sided heart failure due to primary disorder of the respiratory system ie pulmonary hypertension
What are the 3 main types of drugs used to treat heart failure?
- Diuretics
- ACE inhibitor
- Beta-blocker
Which class of diuretics are usually used in heart failure management? Give an example, and where it works:
Loop diuretics
- Furosemide
- Loop of Henle, blocks NKCC2 (Na+-K+-2Cl symporter)
May be used with Aldosterone antagonists (K+ sparing diuretics):
- Spironalactone
- Late DCT + Collecting duct, prevents aldosterone-mediated AQP2 insertion in apical wall of principal cells
