Acute Left Ventricular Failure

Introduction

Acute left ventricular failure is a sudden diminution in the function of the left ventricle. when this happens, pulmonary capillary and venous pressure increase beyond plasma oncotic pressure. There is resultant accumulation of oedema fluid in the pulmonary interstitial spaces and alveoli.

Aetiology

  • Hypertension
  • Myocardial infarction
  • Arhythmias

Clinical features

  • Dyspnoea
  • Orthoponea
  • Paroxysmal nocturnal dyspnoea
  • Cough
  • Heamoptysis
  • Restlessness
  • Wheezes
  • Hypoxia

Differential diagnoses

  • Pulmonary thromboembolism
  • Bronchial asthma
  • Cardiac tamponade

Complications

  • Acute renal failure
  • Right-sided heart failure

Investigations

  • Plain chest radiograph
  • Electrocardiography
  • Echocardiography
  • Pulmonary function tests
  • Arterial blood gasses
  • Electrolyte, Urea and Creatinine
  • Cardiac catheterization

Treatment objectives

  • To improve pump performance of the failing ventricle
  • To reduce the cardiac workload
  • To control salt and water retention

Non-drug treatment

Drug treatment

Diuretics

Furosemide

  • Adult: 40 – 80 mg by slow intravenous injection stat, then 40-160 mg orally or intravenously daily in 1or 2 divided doses for maintenance.
  • Child:
    • Neonate: 0.5 – 1 mg/kg by slow
      intravenous injection every 12 24 hours (every 24 hours if post-menstrual age is under 31 weeks)
    • 1 month – 12 years: 0.5-1 mg/kg (maximum 4 mg/kg), repeated every 8 hours as necessary
    • 12 – 18 years: 20 – 40 mg every 8 hours; higher doses may be necessary in resistant cases

Angiotensin Converting Enzyme Inhibitors

Captopril

  • Adult: 6.25-12.5 mg daily orally, then 25 mg in divided doses daily (maximum 150 mg daily) for maintenance
  • Child: not licensed for use in children

Or:

Lisinopril

  • Adult: 2.5 mg orally daily; 5 – 20 mg daily for maintenance
  • Child:
    • Neonate, initially 10 μg/kg orally once daily; monitor blood pressure
      carefully for 1 – 2 hours, increased as necessary up to 500 μg/kg daily in 1-3 divided doses
    • 1 month 12 years: initially 100 μg/kg orally once daily, monitor blood pressure carefully for 12 hours, increased as necessary up to a maximum of 1 mg/kg daily in 1-2 divided doses
    • 12 – 18 years: initially 2.5 mg daily, monitor blood pressure carefully for 1-2 hours; usual maintenance dose 10 – 20 mg daily in 1 – 2 divided doses (maximum 40 mg daily if body weight is >50 kg).

Morphine

May require morphine

  • Adult: 5-10 mg orally, subcutaneously or intramuscularly (usually a single initial dose)
  • Child: not listed for this indication

Digoxin

  • Adult: 125-250 μg orally daily may be required

Aminophylline

  • Adult: up to 250 mg by slow intravenous injection stat

Supportive measures

  • Oxygen
  • Nurse in cardiac position

Notable adverse drug reactions, caution and contraindications

  • Use ACE inhibitors, aminophylline and digoxin with caution
  • Monitor potassium levels closely
  • Monitor fluid input and output

Prevention

  • Adequate control of hypertension