Cardiac failure (acute and chronic) Flashcards
What is the generic defintion of cardiac failure?
The Failure of the heart to maintain the cardiac output (CO) needed to meet the body’s requirements
CO = HR x SV
What is chronic HF?
Chronic Heart Failure: A long-term condition in which the heart fails to maintain an adequate circulation for the needs of the body.
What are some features of chronic HF?
Ø Develops and progresses slowly
Ø Can have periods of acute decompensation
What is acute HF?
Rapid onset or worsening of symptoms & signs of HF, requiring urgent Tx and evaluation.
What is low output HF?
CO is ↓ and fails to increase normally with exertion
What is high output HF?
CO is normal but you have ↑ needs (e.g. hyperthyroidism, pregnancy).
Heart failure occurs when the heart fails to meet those increased needs (the heart is overworked).
What is congestive HF?
When LHF and RHF occur simultaneously
What is the major sign of congestive HF?
- breathless (sign of LVF) &
- oedema (sign of RHF)
due to abnormal salt and water retention
What are the 3 major causes & examples of LHF?
1)Valvular:
- ØAortic stenosis,
- ØAortic Regurgitation
- ØMitral Regurgitation
2) Heart Muscle:
- ØIschaemic Heart Disease
- Cardiomyopathy
- Myocarditis
- Arrhythmias (AF)
3) Systemic:
- Ø Hypertension,
- Ø Amyloidosis
- Ø Drugs (e.g. cocaine, alcohol, BBs*, chemotherapeutics - eg doxorubicin)
Why does aortic stenosis cause LHF?
causes excessive afterload.
Basically the ventricle has to push harder to eject blood from a stenosed aortic valve.
(NB: afterload = the pressure the heart must work against to eject blood during systole)
Why does aortic regurgitation cause LHF?
There is increased pressure in the LV due to the regurgitant blood form the aorta to the LV
(the LV in addition to having to pump the normal volume of blood, has to pump the regurgitant blood as well).
These changes lead to cardiac remodeling (dilatation, hypertrophy) leading to heart failure.
Why does mitral regurgitation cause LHF?
If significant (moderate to severe) MR is present, the Left Ventricle must work harder to keep up with the body’s demands for oxygenated blood.
Over time, the heart muscle and circulatory system undergo a series of changes to maintain this increased demand – due to mechanical overload the LV overtime can become, hypertrophied, fibrotic, dilated and scarred, ending up with an impaired myocardial function.
This can lead to LHF (mitral regurgitation increases preload)
Why does HTN cause LHF?
increases afterload.
LV has to push harder in order to push blood against high systemic pressures.
This over time puts strain in the LV leading to LHF.
Why does amyloidosis cause LHF?
In amyloidosis, an abnormal protein called amyloid builds-up in tissues and organs.
If amyloid gets deposited in the heart, the heart becomes increasingly stiff and eventually the pumping function deteriorates.
Give examples of drugs that can cause LHF
- cocaine
- alcohol,
- chemo,
- betablockers (negative chrono & ino tropic effect)
As beta blockers used to be contraindicated in HF, which ones are now recommended?
- metoprolol succinate
- bisoprolol,
- carvedilol
What are the most serious cardiac side effects of beta blockers?
- symptomatic hypotension
- unacceptable fatigue
- exacerbation of heart failure in patients with acute decompensated heart failure
What are some non-cardiac side effects of beta blockers?
- depression
- fatigue
- dizziness
- bradycardia
- sexual dysfunction
What are the 3 main causes & examples of RHF?
1) LHF
2) Lungs:
- Ø Pulmonary HTN (can lead to cor pulmonale)
- Ø PE
- ØChronic Lung Disease (interstitial lung disease, pulmonary fibrosis, cystic fibrosis)
3) Heart valves:
- ØTR
- Ø Pulmonary valve Disease e.g. Pulmonary stenosis or Pulmonary regurg.
What is cor pulmonale?
Enlargement and failure of RV due to increased pressure in the lungs/vascular resistance
Why does pulmonary HTN cause RHF?
heart cannot pump to the stiffened pulmonary arterial vessels. So RV needs to work harder, becomes enlarged and weakened
Why does chronic lung disease cause RHF?
can result in chronic hypoxia:
- The pulmonary vasculature results to chronic hypoxia by vasoconstriction.
- This increases vascular resistance and and results in increased pulmonary arterial pressure.
- The right heart reacts to this by remodeling (hypertrophy and dilatation).
- Over time it can lead to RHF.
Why does tricuspid regurgitation cause
Why does TR cause RHF?
increases preload –>
mechanical overload the RV can become, hypertrophied, fibrotic, dilated and scarred, ending up with an impaired myocardial function.
This can lead to LHF (mitral regurgitation increases preload)
Why does pulmonary stenosis cause LHF?
causes excessive afterload.
the ventricle has to push harder to eject blood from a stenosed pulmonary valve.
(NB: afterload = the pressure the heart must work against to eject blood during systole)