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Heart Failure

From Mediwikis

Inability of the heart to function as a pump and maintain sufficient cardiac output to perfuse the body. The normal adaptive responses of the cardiovascular system that help maintain perfusion in acute situations cause damage if needed over a prolonged period.

Clinical Presentations

Left and Right Heart Failure

Left Heart Failure Right Heart Failure
Aetiology
  • Ischaemic Heart Disease
  • Hypertension
  • Valvular Heart Disease
  • Cardiomopathy
  • Other
    • Congenital
    • Alcohol
    • Drugs (Chemo)
    • Hyperdynamic circulation (e.g. - anaema, thyrotoxicosis, paget's)
    • Pericardial disease
  • Secondary to left heart failure (both failed - "congestive")
  • Infarct - right ventricle
  • Pulmonary hypertension
  • Pulmonary embolism
  • Cor pulmonale
  • COPD
Symptoms
Pulmonary congestion
  • Fatigue
  • Exertional dyspnoea
  • Orthopnoea
  • Paroxysmal noctural dyspnoea
  • Cough
Non-specific
  • Fatigue
  • Anorexia
  • Nausea
Signs
Pulmonary congestion
  • Tachypnoea
  • Tachycardia
  • Displaced apex
  • Basal lung crackles
  • 3rd heart sound (due to rapid ventricular filling)
  • Mitral regurgitation (if severe)
  • Raised JVP
  • Hepatomegaly
  • Pitting oedema - ankles & calves if active patient, sacrum if bed
  • Tricuspid regurgitation (right ventricular dilatation -> giant 'V' waves in JVP & tender liver)
  • Ascites
  • Pleural effusion (if secondary to RHF)

Congestive Heart Failure (CHF)

Both sides of the heart fail, usually with right heart failure coming secondarily to left heart failure. Symptoms are a combination of left and right.

Acute Heart Failure

  • Minutes -> Hours
  • Left/Right

Aetiology

  • Myocardial infarction
  • Pulmonary embolism
  • Cardiac tamponade

In Paediatrics

Ventricular Septal Defect- most common

  • Harsh, Pansystolic murmur
  • Parasternal Thrill

Atrioventricular Septal Defect

Patient Ductus Arteriosus

  • Machinery murmur (continuous)
  • Collapsing Pulse

Compensatory Mechanisms (that cause damage over chronic period)

  • Sympathetic Nervous System
    • Acutely: ↑ HR & SV
    • Chronic: Arteriolar constricton -> ↑ afterload -> ↓ cardiac output
  • Renin-Angiotensin System
    • Acutely: ↑ fluid retention -> ↑ venous pressure -> ↑ stroke volume
    • Chronic:
      • Retention -> Congestion -> Oedema -> Dyspnoea
      • Angiotensin II -> Arteriolar constriction -> ↑ afterload -> ↓ cardiac output
  • Ventricular Dilatation
    • Acute: ↑ stretch -> ↑ Starlings -> ↑ stroke volume
    • Chronic: No Starling's from other factors -> ↑ myocardial systolic tension needed -> ↑ O2 requirement

Chest radiograph findings

  • Cardiomegaly (heart size > 50% thoracic diameter on PA film)
  • Pulmonary oedema ("bat wing" shadowing)
  • Upper lobe diversion (swollen vessels in upper zones)
  • Kerley B lines (thin horizontal lines from lateral lung margins inwards)
  • Pleural effusions

Treatment

More information at Heart Failure Treatment

  • Maintain Oedema free
    • Loop diuretics-Furosemide
    • Potassium sparing diuretic-Spironolactone
    • Fluid and Salt Restriction
  • Inhibition of Renin Angiotensin System/Neurohumoral Activation
    • ACE inhibiters
  • Inhibition of neurohormonal activation of the heart
    • Beta blockers
    • Previously believed to be contraindicated as beta blockers are a negative inotrope (reduce cardiac function) however patients on long term inhibition of their maladaptive neurohormonal responses do better
  • Reduce further CVD risk:
    • Statin, Aspirin, Antiplatelets

Complications

  • Medication is complex both for patients and doctors
  • Most medications reduce BP which can only be reduced so far
  • Electrolytes and renal function must be closely monitored
  • People with heart failure have increased risk of sudden cardiac death