Cardiac failure (acute and chronic) Flashcards
What are the different types of heart failure?
HFrEF = heart failure with reduced ejection fraction
HFpEF - heart failure preserved ejection fraction
Define HF.
What is the CO equation?
The failure of the heart to maintain the cardiac output (CO) needed to meet the body’s requirements
CO= HR x SV
How common is HF?
Incidence increases rapidly with advanced age:
- -1-2% of those <70 yrs
- -10-20% of those > 70 years
Define chronic HF.
A long-term condition in which the heart fails to maintain an adequate circulation for the needs of the body.
- Develops and progresses slowly
- Can have periods of acute decompensation
Define acute HF.
Rapid onset or worsening of symptoms & signs of HF, requiring urgent treatment and evaluation.
What is the pathophysiology of HF?
SNS –> increased HR and SV –> increased CO
Long term activation of SNS can have a -ve effect =increased wall stress, dilation, ventricular remodelling –> disease progression and further SNS activation
Left ventricular remodelling = change in ventricular size, shape, function which could be due to MI, HTN, cardiomyopathy, valvular disease.
Hallmarks include hypertrophy, loss of myocytes and interstitial fibrosis –> left ventricle dilates, assuming more globular shape –> mitral regurgitation
MR –> increasing volume overload and progresison of HF
What is the difference between high and low output cardiac failure and which is more common?
Low output HF - CO is reduced and fails to increase normally with exertion - MORE COMMON
High output HF - CO is normal but you have increased need (e.g. hyperthyroidism, pregnancy). HF occurs when heart fails to meet those increased needs (heart is overworked)
What is congestive heart failure?
When RHF and LHF occur together.
CCF is a term used for patients who are breathless with oedema due to abnormal salt and water retention (signs of LVF and RVF)
What is the aetiology of left heart failure? (reduced CO state)
1)Valvular:
- Aortic stenosis,
- Aortic Regurgitation
- Mitral Regurgitation
2) Heart Muscle:
- Ischaemic Heart Disease
- Cardiomyopathy
- Myocarditis
- Arrhythmias (AF)
- Congenital
- Pericardial
3) Systemic:
- Hypertension,
- Amyloidosis
- Drugs (e.g. cocaine, alcohol, BBs*, chemotherapeutics - eg doxorubicin
How does aortic stenosis contribute to LHF?
Aortic stenosis → causes excessive afterload as ventricle has to push harder to eject blood.
(NB: afterload = the pressure the heart must work against to eject blood during systole)
How does aortic regurgitation cause LHF?
Aortic regurgitation: 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.
How does mitral regurgitation cause LHF?
Mitral regurgitation: If significant (moderate to severe) MR is present, the LV 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)
How does hypertension cause LHF?
Hypertension: 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.
How does amyloidosis cause LHF?
Amyloidosis: 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.
Why can beta blockers exacerbate HF?
BBs can exacerbate the HF, bc they have negative chronotropic and inotropic effects –> symptomatic hypotension and acute decompensated HF
But selective beta1‐blockers or non‐selective combined alpha‐ and beta‐blockers are now a part of the standard treatment of heart failure since a number of trials showed beneficial effects
metoprolol, bisoprolol, or carvedilol
What is the aetiology of RHF? (reduced CO state)
1) LHF
2) Lungs:
- Pulmonary HTN (can lead to cor pulmonale)
- PE
- Chronic Lung Disease (interstitial lung disease, pulmonary fibrosis, cystic fibrosis)
3) Heart valves:
- TR
- Pulmonary valve Disease
How does pulmonary hypertension cause RHF?
Heart cannot pump to the stiffened pulmonary arterial vessels. So RV needs to work harder, becomes enlarged and weakened.
How does chronic lung disease cause RHF?
Chronic lung disease 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 remodelling (hypertrophy and dilatation). Over time it can lead to RHF.
What is the aetiology of high output HF?
Caused by conditions that require a ↑ CO and put strain on the heart.
2 things that medical students need to deal with a high output state: NAP MEALS
- Nutritional (B1: thiamine)
- Anaemia
- Pregnancy
- Malignancy (multiple myeloma)
- Endocrine (hyperthyroidism)
- AV malformations
- Liver cirrhosis
- Sepsis
High output HF initially presents with RHF then LHF
What are the signs and symptoms of LHF vs RHF?
LHF: respiratory symptoms due to fluid accumulation in the lungs
RHF: symptoms due to fluid accumulation in the periphery
- So since the LV pumps the blood coming from the lungs to the rest of the body, if the LV fails fluid will accumulate into the lungs causing symptoms*
- Accordingly, if the RV that pumps blood coming from the peripheries fails, fluid will accumulate in the periphery.*
What are the symptoms of LHF? What are the signs?
Symptoms:
- Exertional dyspnea
- Orthopnoea (SOB when lying flat)
- Paroxysmal nocturnal dyspnea – PND (attacks of SOB at night)
- Fatigue
- Nocturnal Cough (+/- pink frothy sputum)
- Wheeze
Signs:
Heart:
- ↑HR, ↑RR
- Irregularly Irregular heart beat (AF often co-exists)
- Pulsus alternans- alternating strong and weak pulses
- Displaced apex beat
- S3 Gallop rhythm
- S4 in severe HF
- Murmur (AS, MR, AR)
Lungs:
- Fine end-inspiratory crackles at lung bases (pulmonary oedema)
- Wheeze (cardiac asthma)