ARRHYTHMIAS - BRADYCARDIA

Recognition

Sinus Bradycardia

Definition

• Bradycardia is defined as a heart rate less than 50 beats per minute (BMJ best practice).

Risk Factors

• Taking medicine known to cause bradycardia
• Age > 70 years
• Previous myocardial infarction
• Hypothyroidism
• Electrolyte disturbances

Causes

• Sinus node dysfunction or conductive system dysfunction
  • Intrinsic
    • Inflammation
    • Infection
    • Degeneration due to age
    • Congenital
  • Extrinsic
    • Toxins
    • Medications
    • Electrolyte imbalance

History

• If possible, ascertain if patient has:
  • Previous admissions with chest pain or cardiac conditions
  • Been diagnosed with a cardiac condition
  • Been taking medication for a cardiac condition
  • Had any operations on their heart
  • Any allergies

General symptoms

• Shortness of breath (dyspnoea)
• Cyanosis
• Chest pain
• Fatigue
• Dizziness
• Reduced exercise tolerance
• Collapse

General Signs

• Tachypnoea following pulmonary oedema from heart failure secondary to bradycardia
• Cool peripheries
• Bradycardia on palpation of pulse
• Hypotension
• Jugular venous distension from heart failure secondary to bradycardia

Initial Assessment and Investigations

• ABCDE assessment
• Assess patient’s airway
• Monitor oxygen saturations and respiratory rate
• If patient is hypoxic give Oxygen (O₂) to achieve target saturations. Initially give 15 L/min via a reservoir mask if the patient is acutely unwell
• Target saturations:
  • 94-98% for patients not at risk of hypercapnic respiratory failure
  • 88-92% for patients at risk of hypercapnic respiratory failure due to conditions such as Chronic Obstructive Pulmonary Disease (COPD)
• Examine patient’s chest
  • Listening for:
    • Bibasal crepitations
    • Cardiac wheeze
• Arterial blood gas (ABG) if concerned about patient’s ventilation
• Chest X-ray if concerned about patient’s ventilation. If the patient is unwell request a portable X-ray
• Obtain intravenous access by placing 2 large bore cannulae in the antecubital fossa. Take blood to check Full Blood Count (FBC), Urea and Electrolytes (U&Es), Liver Function Tests (LFTs), Calcium, Magnesium, Glucose and Venous Blood Gas (VBG)
• Check Capillary Refill Time (CRT) - hold for five seconds and refilling should occur in 3 seconds
• Assess pulse rate, rhythm and character
  • If no pulse present start advanced life support
• Monitor heart rate and blood pressure
• Listen to patient’s heart sounds
• 12 lead Electrocardiogram (ECG)
• Call for senior help
• Attach patient to cardiac monitor
• Identify underlying cause and treat
• Identify adverse features:
  • Shock
  • Syncope
  • Myocardial ischaemia
  • Heart failure
• Check patient’s urine output and consider catheterisation
• Check pupils are equal and reactive
• Assess Glasgow Coma Scale or ACVPU using the NEWS2 chart
• Check patient’s temperature and blood sugar
• Examine patient’s abdomen and legs
• Consider venous thromboembolism prophylaxis

Response

Immediate management

• Follow RESUS guidelines

Bradycardia algorithm

Referrals

• Discuss with senior member of the team
• Contact critical care outreach team
• Referral to cardiologists
• Referral to anaesthetists if cardioversion is required
• Consider referral to Intensive Care Unit (ICU) if:
  • Failure to respond to medical management
  • Patient requires ventilator support
  • Patient requires blood pressure support
  • Deterioration of blood gas following medical management

Future management

• Review by cardiologists regarding future management
  • Medical
  • Pacemaker