Lecture 5 LV Dysfunction and Heart Failure I Flashcards
What is the NICE definition of heart failure
A complex clinical syndrome of symptoms and signs that suggest the efficiency of the heart as a pump is impaired
What is the ESC definition of heart failure
An abnormality of cardiac structure or function which leads to failure of the heart to deliver oxygen at a rate commensurate with the requirement of the tissues despite normal filling pressures or only at the expense of increased filling pressures
How many patients per year in the UK experience heart failure
1 million
Heart failure will increase in incidence by 50% in the next 5 years T or F
T
What is the main risk factor of heart failure
Age – heart failure is a disease of ageing it is rare below 65 but extremely common in the over 85
Why is it thought that heart disease affects more men than women
Most likely underlying coronary artery disease which is more prevalent in males
What percentage of hospital admissions is accounted for by heart failure
5%
Heart failure accounts for 2% of the NHS budget. Where is most of this cost incurred
70% of heart failures cost to the NHS is on hospital admission
What is the prognosis of heart failure
Heart failure prognosis is extremely poor with an overage 30% mortality within 1 year
What causes the majority of heart failure
Left ventricular systolic dysfunction (LVSD)
Other than LVSD what other category of heart failure is there
Heart failure with preserved ejection fraction (HFPEF)
How can problems with diastole cause heart failure
Relaxation of the heart in diastole isn’t passive it’s an active energy dependent process requiring ATP. Thus patients can have problems with this and hence have heart failure with preserved ejection fraction
How can we classify heart failure based on its onset
Acute heart failure is when a patient suddenly deteriorates whereas chronic heart failure is a creeping worsening state that gradually gets worse over time
Give an example of a structural cause of heart failure
Mitral valve rupture can sometimes cause heart failure
What is the most common cause of heart failure
Coronary artery disease
Discuss why treatments of heart failure don’t target the heart itself
Drugs that stimulate the heart when its poorly contracting increase the energy requirements by the heart. When a patient is in heart failure a neurohumoral response triggered in response to decreased cardiac output this is an attempt to support the circulation. However this response can be derogatory and increased the demands of the heart. So instead treatments are therefore aimed at the response not at the heart itself.
What is the main target in heart failure treatment
The main approach is a vasodilator therapy that acts via neurohormonal blockade. This includes blocking the renin-angiotensin-aldosterone system and the sympathetic nervous system.
What is the difference between left ventricular dysfunction and heart failure
LV dysfunction is something you can measure by measuring the ejection fraction whereas heart failure is the clinical syndrome observed
What are the two broad effects of heart failure
Reduced cardiac output and increased filling pressures/preload
What causes reduced cardiac output in patients in heart failure and how does this present
Reduced cardiac output is often due to decreased ejection fraction. Patients will present with fatigue and exercise intolerance
What causes the increased filling pressures/preload in heart failure
There is an increased back pressure upstream of the ventricles because the ventricles aren’t clearing as much blood. This means that the veins leading to the ventricles increase in pressure
What symptom is associated specifically with LVSD in heart failure
Pulmonary oedema due to increased pressure in the left atria backtracking to the pulmonary veins subsequently increasing pressure in those vessels. This causes fluid to leave the vessels and enter the lungs
How do patients with pulmonary oedema usually present
Patients are extremely uncomfortable and want to be sat up in order to decrease pulmonary pressure an used all respiratory muscles
What is the dominant symptom in patients with heart failure and how does this present
The dominant symptom is venous congestion which presents as breathlessness during minor exertion
What symptom is associated specifically with right ventricular dysfunction in heart failure and how does this present
Peripheral oedema due to increased pressure in the right atria backtracking to the all of the veins. This presents as swelling of the lower limbs and abdomen (Ascites)
What is meant by anasarca
‘Michelin man effect’ where oedema has travelled far up the body
Why is the increase in filling pressure that occurs in heart failure as a result of the ventricles diminished ability to clear blood of little benefit to patients
The steepness of the Frank-Starling curve is much shallower in these patients so therefore increases in preload/filling pressures wont increase cardiac output by any significant amount
What is synonymous with preload
Filling pressure left ventricular end diastolic pressure end diastolic volume
Diuretics and venodilators can cause hypotension in healthy patients why does this often not occur in patients in heart failure
Due to the much shallower Frank-Starling curve these drugs can shift patients out of pulmonary congestion with very little loss of cardiac output
What are the main broad effects of diuretics
Cause the body to lose Na+ and water
What are the main clinical indications for diuretics
Heart failure hypertension
What are the 4 main classes of diuretics
Thiazide diuretics loop diuretics K+ sparing diuretics and aldosterone antagonists
Which region of the nephron do thiazide related drugs act on
Distal tubule
Which region of the nephron do loop diuretics act on
Loop of Henle
Which classes of diuretics are relatively week
Thiazides and aldosterone antagonists
Which diuretics are mainly used in hypertension and not heart failure
Thiazide diuretics
Which diuretics are most commonly used in heart failure
Loop diuretics
Which class of diuretics aren’t used in heart failure because there are better alternatives
K+ sparing diuretics
Which class of diuretics have added value in heart failure patients and why
Aldosterone antagonists have added value in heart failure patients because as well as lowering blood volume they also supress the RAAS system. Hence they are ideal in the treatment of heart failure
Give some examples of thiazide like drugs
Chlorothiazide Bendroflumethiazide chlortalidone
What are the main loop diuretics
Furosemide and bumetanide
Which class of diuretics have a strong diuretic effect
Loop diuretics
Why are some patients on loo diuretics on massive doses
If the intrinsic function of the kidney is impaired as well/due to the heart failure then furosemide doesn’t work so well because it needs to be metabolised by the kidney first. Hence these patients are put on large doses
Give some examples of K+ sparing diuretics
Spironolactone eplerenone amiloride triamterene
Which K+ sparing diuretics are sometimes used in heart failure and why
Spironolactone and eplerenone have added value in that they are aldosterone antagonists. So therefore they are sometimes used in heart failure
Amiloride if often used to treat patients in heart failure T or F
F
Eplerenone is a much more expensive diuretic than spironolactone why are some patients switched onto this drug
Spironolactone is a pseudoestrogen that is associated with gynaecomastia and breast pain in males. Hence its sometimes necessary to switch patients to eplerenone
What are the adverse effects of diuretics
Hypotension hypovolaemia hyponatraemia hypomagnesaemia hypocalcinaemia hyperuricaemia
Which class of diuretics mainly causes hypotension and hypovolaemia
Loop diuretics
What are the unique side effects with thiazide diuretics
Erectile dysfunction and impaired glucose tolerance
What is the effect of isosorbide dinitrate
Causes vasodilation
Below is some data from the isosorbide dinitrate/hydralazine trial comparing this combination therapy with placebo and another vasodilator prazosin. Describe what this data shows
Placebo group patients had a 50% mortality within 3 years. Prazosin treated patients has an almost identical mortality to placebo. Interestingly hydralazine/Isosorbide resulted in a 36% mortality reduction compared to placebo. Hence this treatment results in a significant risk reduction in mortality in heart failure patients. This is the first evidence that vasodilators actually increased outcomes and prognosis in patients with heart failure
Hydralazine in combination with isosorbide dinitrate also increases LVEF T or F
T
What treatment is used in heart failure patients if modern treatments fail
Hydralazine/isosorbide dinitrate
