2 min read - Bradyarrhythmias

An elderly lady was brought to casualty medical unit of a tertiary care hospital with the complaint of faintishness for several hours. There was no history of chest pain, palpitations, fever, vomiting or diarrhoea.

She was a known patient with hypertension for which she was on several medications.

On examination she was pale looking and sweaty. Her pulse rate was 36/min. Blood pressure was 80/60mmHg.

1. What is the probable diagnosis?
  • Brady-arrhythmia causing hemodynamic instability.
2. What are you going to do?
  • Be HAPPY that you are in a tertiary care centre!
  • Initial priority is to improve patients hemodynamic parameters
  • Easiest way is to correct the BRADYCARDIA!
  • But until you find what it is and correct it, you may try the following
    • Raise the foot end
    • IV fluid boluses
    • IV atropine
      • Give as boluses
      • 0.6mg every 3-5 minutes
      • You may give up to 5 vials
    • If there's no response you can try other inotropic drugs.
      • Adrenaline
      • Dobutamine
  • In many patients the only effective mode of treatment is cardiac pacing
    • External pacing
    • Temporary pacing
    • Insertion of a permanent pacemaker
HOMEWORK
  • Read a bit about pacing
  • Ask a registrar to demonstrate how to perform external pacing!
3. What might you see on the ECG? 

Go through the ECG and make your diagnosis before you see the comments below!


  • The rate is? Is it regular?
  • There are p waves.
  • Following each p wave there're QRS complexes.
  • THIS IS SINUS BRADYCARDIA

  • The rate is? Is it regular?
  • There are p waves
  • Following some p waves you dont see QRS complexes
  • If you closely go through it, you will note that p waves follow its own rate while QRS complexes follow a different rate.

  • So this is a COMPLETE HEART BLOCK
HOME WORK
  • Find out other patters you might see on the ECG in patients with bradycardia.

4. What are the causes for bradycardia
  • Any disease which can affect the conduction pathway starting from sinus node can lead to bradycardia.
  • Common causes are
    • Sick sinus syndrome
      • The sinus node is sick!
    • Myocardial infarction
      • It can affect any part of the conduction system
      • Common bradyarrhythmias are sinus bradycardia and complete heart block
  • Some endocrine diseases can cause bradycardia. But it's unlikely for them to present acutely like in this patient.
    • Hypothyroidism.
  • Other conditions which can affect the heart
    • Myocarditis
    • Infective endocarditis

CAUSES THAT YOU SHOULD NEVER FORGET
  • KANERU poisoning
  • ORGANOPHOSPHATE poisoning
  • BETA BLOCKER overdose
If a medical student presents with bradycardia, the most likely cause would be hypothermia!

HOME WORK
  • What are drugs/ poisons can cause bradycardia?
  • Find out the antidotes/ management of each of those drugs/ poisons!


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