Heart Failure Flashcards
(35 cards)
Define heart failure
Pathophysiological process in which the heart as a pump is unable to meet the metabolic requirements of the tissues for oxygen and substrates despite the venous return to the heart being either normal or increased.
What are the 3 compensatory mechanisms of Heart Failure?
-Increased preload -Increased heart rate -Increased systemic resistance
What does the Frank Starling mechanism state?
The stroke volume of the LV will increase in proportion to the amount of blood in the left ventricle ie increased venous return/preload will cause an increased in myocardial stretching–> increase in stroke volume (due to myocyte stretch causing a more forceful systolic contraction
The Starling curve represents the relationship between which two cardiac parameters?
preload
cardiac output
The Starling curve shows that the force of contraction is proportional to what?
The preload or the initial length of the cardiac muscle fiber
What happens when the Starling Curve can no longer compensate in heart failure?
increased preload–> Increase in myocardial stretching–> increase in stroke volume–> increase in cardiac output
THEN; reaches a PLATEAU—> DECOMPENSATION—> reduction in stroke volume–> causing interstitial oedema
How does chronic activation make decompensated HF worse?
- VASOCONSRICTION: further exacerbates heart failure by increasing afterload
- Myocardial apoptosis
- Increased intravascular volume–>release of ANP and BNP
What effect do the compesnatory mechanisms have?
increased prelaod, afterload and heart rate+ prioritisation of blood flow to vital organs
- this increases cardiac work–> cellular hypertrophy and myocardial demand ischaemia
- causing cellular necrosis and apoptosis–> worsening cardiac function and increased reliance on compensatory mechanisms
Classify systolic and diastolic heart failure in terms of ejection fraction
- Systolic HF; REDUCED EF ie heart cannot pump
- Diastolic HF; PRESERVED EF ie heart cannot fill
WHY can’t the heart fill in diastolic HF?
Walls are stiff and thick
- less compliance of the heart
- cannot get a good volume into the left ventricle because the EDV is restricted therefore SV is also affected
the stiff ventricles fill with less blood than normal
Give some common causes of HF
- IHD
- HTN
- inherited or acquired cardiomyopathies
eg Inherited Hypertrophic cardiomyopathy, Restricted cardiomyopathy, Dilated cardiomyopathy
DM
Valve disease
Name 2 rare drugs which can cause HF
- Biologics; monoclonal antibodies
- ANTHRACYCLINES; cancer drugs used for breast cancer and haematological malignancies
Name some causes of LHF
Pump failure:
- Heart muscle disease; IHD, cardiac muscle myopathy
- Restricted filling; pericarditis, tamponade
Excessive preload:
- mtiral regurgitation
Chronic excessive afterload:
- atrial stenosis
- hypertension
Name some causes of RHF ?
- INTRINSICE; RV infarciton
- Volume overload; pulmonary and trsicuspid regurgitation, SHUNTS; VSD and ASD
- increased afterload; Left HF, PE, chronic lung disease
Give 4 symptoms of LHF
- SOBOE
- Orthopnoea
- Paroxysmal Nocturnal Dyspnoea
- Nocturnal cough with or without pink frothy sputum
Give 6 signs of left heart failure
- Tachycardia
- Tachypnoea
- Cardiomegaly
- Third heart sound ie S3
- Pulmonary crackles
- Pleural effusion
Give 5 syptoms of RHF
- Swollen ankles
- Dyspnoea
- Fatigue
- Anorexia
- Nausea/loss of appetite
Give 4 signs of RHF
- Pitting oedema
- Hepatomegaly
- Ascites
- Raised JVP+ jugular venous distension
How is Dyspnoea with HF classified?
NYHA-New York Heart Association
Class I:Heart disease present but no undue dyspnoea/NO LIMITATION ON PHSYICAL ACTIVITY
Class II: Comfortable at rest but dyspnoea with ordinary activities
Class III: Less than ordinary activity causes dyspnoea, limiting lifestyle; marked limitation on physical activity
Class IV: Dyspnoea present at rest
How does an ECG help in diagnosis of HF?
Helps to identify causes of AHF and ischaemia
- can get ventricular tachycardia, arrythmias, AF, LVH
- Patthological Q waves indicate previous MI
- Do a Hb level; checking for anaemia, FBC
*
Describe the pharmacological actions of BNP:
a) Haemodynamic
b) Neurohormonal
c) Cardiac
d) Renal
Haemodynamic: balanced vasodilation on veins, arteries and coronary arteries
Neurohormonal:
- decreased aldosterone
- decreased endothelin
- decreased norepinephrine
Renal: increased diuresis and increased natriuresis
Cardiac:
- anti-fibrotic
- anti-remodeling
- iusiotropic
What are the 3 main investigations always done to investigate heart failure?
- ECG
- ECHO
- BNP
What is your diagnosis if BNP and ECG are normal?
if both of these are normal, HF is unlikely. no need to do any more cardiac tests
What other investigations would you carry out for suspected HF?
Bloods - FBC, U&E, BNP, TFT, LFT, cholesterol, glucose, eGFR
CXR
Echo
ECG
