Heart Failure

The term “heart failure”(HF) describes an abnormality of the cardiac structure/function that leads to failure of the organ to deliver oxygen sufficient in rate to the metabolising tissues, despite normal filling pressures.

It is actually a blanket term that covers a broad range of pathologies, but usually presents with specific signs and symptoms;

  • Breathlessness
  • Ankle swelling
  • Fatigue
  • Elevation of jugular venous pressure
  • Pulmonary “crackles”
  • peripheral oedema

Precursors of HF encompass asymptomatic pathologies concurrent with progression to HF;

  • Systolic or diastolic LV dysfunction
  • Ischaemia
  • HCM
  • Arrhythmia

Starting the appropriate treatment at the precursor stage, may have a reducing effect on the mortality of patients for whom systolic LV dysfunction is asymptomatic.

Left-Sided HF

  • Systolic failure
    • LV contractility is impaired
    • Ability to pump to maintain circulation is diminished
  • Diastolic failure
    • LV relaxation is impaired
    • LV filling is diminished

Right-sided HF

  • Usually occurs as a result of Left HF
  • Increased fluid pressure pushes blood back through the lungs
  • Blood backs up in the venous system, causing ascites

Congestive HF

  • Blood flow exiting the heart slows
    • Congestion throughout the vascular system
    • Results in oedema (usually legs and ankles)
  • Pulmonary oedema
    • Fluid collection in the lungs
    • Can cause supine S.O.B.

HF affects roughly 1-2% of the adult population, and this figure rises to ≥ 10% in individuals over 70yrs. The risk of HF at 55yrs is currently 33% in males, and 28% in females.

HF can be termed in 3 ways, based on the measurement of the left ventricle ejection fraction (LVEF), that is the percentage of the end diastolic volume ejected with each contraction, which is calculated thusly;

Stroke Volume (ml) = LVEDV – LVESV

LVEF (%) = (Stroke Volume / LVEDV) 100

The subsequent terms, based on the outcome of this equation;

Heart Failure with Preserved Ejection Fraction (HFpEF)

  • LVEF
    • ≥ 50%
  • Raised levels of natriuretic peptides
  • 1 or more of the following;
    • LVH and/or LAE
    • Diastolic dysfunction

Heart Failure with Mid-Range Ejection Fraction (HFmrEF)

LVEF

  • 40 – 49%
  • Raised levels of natriuretic peptides
  • 1 or more of the following;
    • LVH and/or LAE
    • Diastolic dysfunction

Heart Failure with Preserved Ejection Fraction (HFrEF)

  • LVEF
    • <40%

Diagnosis

Due to the non-specific nature of common symptoms, diagnosis can be difficult. This is especially true in the elderly and the obese. Patients suffering chronic lung disease are also difficult to diagnose.

Diagnosis should begin with a thorough patient history, as HF is unlikely in a patient with no relevant markers, such as

  • Previous MI
  • Known CAD
  • Hypertension

Essential investigative measures are;

  • ECG
    • MI markers
    • Bradycardia
    • AF
    • LVH
  • Chest X-Ray
    • Assess lungs
    • External heart structure
  • Lab Tests
    • Cardiac markers
  • Transthoracic Echocardiogram
    • Valvular function
    • LV function

Heart

 

 

 

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