HF part 1 Flashcards
Definition of HF / CF
An inability of the heart to deliver blood (and O2) at a rate proportionate with the requirements of the metabolising tissues, despite normal or increased cardiac filling pressures
Congestive cardiac failure describes a combination of left and right-sided ventricular failure.
Epidemiology of CF
- M>F
- More prevalent with increasing age
Common: 2-10 (20) %
Costly: 2% of the NHS expenditure in the UK
Disabling: The worst quality of life.
Treatable - not really curable
25-50% of patients die within 5 years of diagnosis
RFs
- Prev MI - greatest RF
- Male, age
- IHD
- HT
- DIabetes
- Renal failure
- AF
Causes of HF
- Myocardial dysfunction - greatest cause
- HT
- Alcohol
- Cardiomyopathy
- valvular
What is HFrEF?
HF with reduced ejection fraction
What is HFpEF?
HF with preserved ejection fraction
Phenotypes of HF
HF due to severe valvular heart disease (HF-VHD)
HF with pulmonary hypertension (HF-PH)
HF due to right ventricular systolic dysfunction (HF- RVSD)
Classes of HF (NYHA)?
Used for assessment of severity of symptoms
Class I: No limitation (Asymptomatic)
Class II: Slight limitation (mild HF)
Class III: Marked limitation (Symptomatically moderate HF)
Class IV: Inability to carry out any physical activity without discomfort (symptomatically severe HF)
What is systolic HF
Inability of the ventricle to contract normally resulting in a
decrease in cardiac output
Systolic HF
- Cardiac output = stroke volume x heart rate
- The ejection fraction is not preserved: an ejection fraction of 40% or less would indicate systolic heart failure.
- The low stroke volume is due to the ventricles not pumping enough blood out.
- HFrEF
Diastolic HF
- Cardiac output = stroke volume x heart rate
- In this case, the stroke volume is low but the ejection fraction is preserved. The reason for the low stroke volume is due to reduced filling of the ventricle (reduced preload)
- HFpEF
Why does right sided HF occur?
- usually occurs as a result of left-sided heart failure.
- Blood starts backing up into the lungs causing pulmonary oedema and congestion
- pulmonary hypertension puts pressure on the right ventricle (cor pulmonale) and causes right-sided heart failure
Causes of systolic failure 1
- Ischaemic heart disease: as less blood and oxygen get to the myocardium, the myocytes start to die
- Hypertension: as arterial pressure increases in the systemic circulation, it gets harder for the left ventricle to pump blood out into that hypertensive systemic circulation.
Causes of Systolic failure 2
- Left ventricular hypertrophy: increased muscle mass requires increased oxygen supply - making it more likely for that the muscle will die
- Dilated cardiomyopathy: heart chambers dilate and thin out, leading to weaker contractions.
Causes of diastolic failure
- Left ventricular hypertrophy: causes the ventricular chamber to decrease in size which means less blood can enter.
- Restrictive cardiomyopathy: ventricle can’t stretch enough to accommodate the blood
- Valvular disease: e.g. aortic stenosis causes LVH or mitral regurgitation means blood doesn’t enter the ventricles in the right amount as it leaks back into atria
- Arrhythmias e.g. atrial fibrillation
Normal heart mechanism
Increased ventricular filling results in increased contraction via the Frank-Starling law→ increased cardiac output
In HF mechanism fails
Pathophysiology of Congestive HF
- As the heart continues to fail →compensatory mechanismsare activated, including anincrease in heart rate,catecholamine releaseandRAAS activation (due to decreased blood flow to kidneys)
- These mechanisms are useful in theinitialperiod but are usuallyoverexpressed, thus instigating avicious cycle.
- Compensatory mechanisms are usually responsible for the fluid retention and fluid overload symptoms experienced by the patient
Signs of Left sided Heart failure
- Tachypnoea and tachycardia
- Cool peripheries
- Peripheral or central cyanosis
- Displaced apex beat
- Stony dull percussion
- Third heart sound (S3)
Symptoms of Left sided HF
- Dyspnoea: particularly exertional
- Orthopnoea (SOB when lying flat) and paroxysmal nocturnal dyspnoea (SOB at night)
- Fatigue and weakness
- Cough with pink, frothy sputum
- Cardiogenic wheeze
Right sided HF signs
- Due to backing up of fluid:
- Raised JVP
- Peripheral pitting oedema
- Hepatosplenomegaly
- Ascites
Symptoms of Right sided HF
- Fatigue and weakness
- Due to backing up of fluid
- Swelling in the legs
- Distended abdomen
Investigations
- NT-proBNP: increased in chronic heart failure
- ECG:broad QRS complexes; evidence of left ventricular hypertrophy
- CXR
- Transthoracic echocardiogram
What is shown on an Chest X ray?
- A-Alveolar oedema (batwing opacities)
- B- KerleyBlines
- C-Cardiomegaly
- D-Dilated upper lobe vessels
- E- Pleural effusion
1st line management
BB (Bisoprolol) + ACEi (Ramipril)
If ACEi intolerant - ARB (Losartan) or hyrdalazine with nitrate
2nd line management
Aldosterone antagonist (e.g. spironolactone) if symptoms not controlled with 1st line management
3rd line management
- Digoxin: an alternative option, particularly for patients with AFand heart failure due to its inotropic effects.
- Ivabradine: an alternative option ifHR >75 bpmandLVEF <35%; slows the heart rate so the heart can pump more blood through the body each time it beats.
- Cardiac resynchronisation therapy(CRT): involves biventricular pacing and forces both ventricles to contract in synchrony, thereby improving cardiac output
Complications of HF
- Pleural effusion:heart failure causes an elevated pulmonary capillary pressure, usually resulting in bilateral transudative pleural effusions
- Acute decompensation of chronic heart failure:patients usually present with acute respiratory distress due to significant pulmonary oedema
- Arrhythmias
- Acute renal failure:reduced cardiac output and drug overuse (ACE inhibitors, aldosterone antagonists, diuretics) results in poor renal perfusion
