IOD LHF

Question 1

definition?

Answer 1

Heart failure is a syndrome which occurs when the pumping action of the heart is inadequate for the needs of the body ie. the cardiac output is unable to meet the metabolic needs of the tissues.

Question 2

prevalence?

Answer 2

It is common: prevalence of 2-3% of population; approximately 20% in 70-80 year olds. It is serious: mortality is 30% in the first year and 10% each year after.

Question 3

classification?

Answer 3

acute or chronic

left or right

Question 4

acute?

Answer 4

In acute left heart failure there is a sudden major insult toLHS
There is no time for compensatory mechanisms to kick in and so contractile force of the LV is greatly reduced, resulting in a catastrophic fall in CO severe congestion in the pulmonary venous system and rapid accumulation of fluid in the alveolar spaces and interstitium-pulmonary oedema and presents as severe SOB. In the worst cases, there is underperfusion of organs and development of cardiogenic shock.

complication of MI affecting the left ventricle
• an extensive MI renders a large volume of the LV non-functional.
• rupture of a mitral valve papillary muscle.
• development of an arrhythmia.

Question 5

chronic?

Answer 5

most common
chronic LV failure
slow damage by chronic IHD, systemic HT, valvular heart disease
compensatory myocardial hypertrophy to maintain CO-asymptomatic
decompensation leading to dilation and falling CO

Question 6

chronic LVF?

Answer 6

progressive disorder-vicious cycle
activation of RAAS and SNS causes VC and sodium and water retention
increases preload and afterload
further stress to LV

Question 7

decompensation progress?

Answer 7

can have acute fluctuations in acute stress eg infections

stability and acute decline

Question 8

systolic?

Answer 8

• the underlying problem is failure of the pumping action of the ventricle during systole.
• usually a consequence of ischaemic heart disease or hypertension.
• the ventricle is usually dilated and fails to contract normally such that the proportion of blood ejected in each beat (normally 50-70%), the ejection fraction, is reduced.

Question 9

diastolic?

Answer 9

• systolic function is not impaired.
• there is failure of the ventricle to fill adequately due to increased stiffness of the wall.
• it may be a consequence of massive LV hypertrophy, myocardial fibrosis or other conditions eg. amyloidosis.
• diastolic LVF is increasingly recognised in older patients.
• diastolic HF accounts for 50% of cases of HF. The prognosis in diastolic HF is the same as for systolic HF.

Question 10

diagnosing LVF?

Answer 10

• History and Examination
• ECG (usually abnormal)
• CXR (cardiomegaly)
• Echocardiography
• can confirm systolic or diastolic dysfunction.
• it may identify the underlying cause eg. aortic or mitral valve disease.
• B type natriuretic peptide (BNP) plasma levels
• BNP is a hormone secreted by ventricular myocytes in response to volume and pressure overload of the LV. Its normal function is to promote a salt and water diuresis by the kidney.
• BNP plasma levels are useful because low levels effectively rule out the diagnosis of LVF.
• in contrast, in the correct clinical context, high BNP plasma levels make the diagnosis of LVF very likely.

Investigations to identify the underlying cause of the heart failure are also important.

Question 11

chronic prognosis?

Answer 11

most common and important

most die within 3 yrs of diagnosis