QuestionSBA
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This is a chelating agent used to reverse an overdose of iron
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Desferrioxamine
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Naloxone is used in the management of opioid overdose
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Naloxone
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N-acetylcysteine is used in the management of paracetamol overdose
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N-acetylcysteine
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IV bicarbonate is used in the management of salicylate (eg. aspirin) or tricyclic antidepressant overdose
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IV bicarbonate
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Glucagon can be used to manage beta blocker overdoses. Atropine may be tried when the patient is bradycardic and haemodynamically unstable (as in this case)
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Glucagon
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Well TIL. Good question
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Anterior Gallbladder
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Evidence is moving away from glucagon being used in BB overdose btw - so you'd be more correct saying bicarb...
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Relapse Retrograde
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# Summary

Bradycardia is defined as a heart rate <60bpm. It may be physiological or pathological. Bradycardic patients may present with fatigue, lightheadedness and/or syncope. Diagnosis of a bradycardia is made on ECG. It a patient has an acute bradycardia and adverse features then this is a medical emergency requiring immediate treatment. Emergency management is according to the Resus Council Algorithm and may involve atropine administration and transcutaneous/transvenous pacing. Longer-term management involves the insertion of a permanent pacemaker. 

# Definition 

Bradycardia is defined as a heart rate <60bpm. If a patient has an acute bradycardia and adverse features (shock, syncope, heart failure or evidence of myocardial ischaemia) then this is a medical emergency requiring immediate treatment. 

# Epidemiology 

The most common cause of pathological bradycardia is sick sinus syndrome and is estimated to have an incidence of 1 in 600 peopel over the age of 65. It affects both sexes equally. 

# Pathophysiology

The pathophysiology of bradycardias depends on the cause. The most common cause of bradycardia is sick sinus syndrome and this is due to the dysfunction of pacmemaker cells within the sinoatrial node (physiological pacemaker) as a person gets older. 

# Classification

Bradycardia can be classified according to cause: 

* Physiological: common in younger populations, athletes and during sleep. 

* Cardiac: 
  * Sick sinus syndrome: disorder of the sinoatrial node. 
  * Heart block: disorder of the atrioventricular node. 
  * Post-myocardial infarction: post-inferior myocardial infarction. The right coronary artery supplies the SAN (pacemaker of the heart). 
  * Aortic valve disease: the right coronary artery origin is disrupted just above the aortic valve. 

* Non-cardiac: 
  * Vasovagal 
  * Endocrinological: hypothyroidism. 
  * Hypothermia 
  * Electrolyte abnormalities
  * Cushing's triad of raised ICP: bradycardia, irregular breathing and hypertension. 
  * Medications: beta-blockers, calcium channel blockers, digoxin etc. 

# Symptoms and signs

## Symptoms

* Lightheadedness 
* Syncope
* Fatigue 
* Shortness of breath

## Signs 

* Nil signs apart from bradycardia 

# Investigations

## Bedside

* **ECG**: help indicate underlying cause for the bradyarrhythmia. E.g. sick sinus syndrome with severe bradycardia and long pauses vs. heart block with prolonged PR interval. 

## Bloods 

* If considering a non-cardiac cause of the bradyarrhythmia (e.g. heart block).

## Imaging 

* TTE: if considering causes such as post-MI (looking for regional wall motion abnormalities) or aortic valve disease. 

# Management

## Initial management

For emergencies, always follow an A-E structure. Identify reversible causes (dyselectrolytaemias, drugs, cardiac causes etc.) 

*If there are adverse signs (e.g. shock, syncope, heart failure, myocardial ischaemia):* 

* **1st line** = **500 micrograms atropine IV**
  * Atropine blocks the vagal nerve which increases firing rate of the SAN. 
* **2nd line** = if the first dose of atropine is not working can consider giving additional doses of atropine 500mcg up to 3mg until response. Alternatively,  **transcutaenous pacing** or **isoprenaline** or **adrenaline** or **alternative drugs** including aminophylline, adrenaline, glucagon (in beta-blocker or calcium channel blocker overdose).  

*If there are no adverse signs but a risk of asystole, or a satisfactory response to 500mcg atropine:*

* Risk of asystole: recent asystole, mobitz type II block, complete heart block + broad QRS, ventricular pauses >3s. 
* **1st line** = administer **500 micrograms atropine IV**.  Alternatively,  **transcutaenous pacing** or **isoprenaline** or **adrenaline** or **alternative drugs** including aminophylline, adrenaline, glucagon (in beta-blocker or calcium channel blocker overdose).  

*If there are no adverse signs and there is no risk of asystole*

* Observe

## Further management 

Transcutaneous pacing may be used as an interim measure whilst awaiting expert help for transvenous pacing/permanent pacemaker insertion. 

# NICE Guidelines

[NICE Guidelines for Symptomatic Bradycardias](https://www.nice.org.uk/guidance/ta88/ifp/chapter/what-is-symptomatic-bradycardia)

# References

[Click here to see the algorithm on the Resus Council website on management of bradycardia](https://www.resus.org.uk/library/2015-resuscitation-guidelines/peri-arrest-arrhythmias)
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Acute bradycardia
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Glucagon is an effective treatment for beta-blocker overdose, particularly in cases of bradycardia and hypotension.
A 75 year old is brought to the emergency department by his son who believes he has taken an intentional overdose of his bisoprolol. On arrival to the department he has a reduced GCS, a blood pressure of 88/58 mmHg, and a heart rate of 40 beats per minute. He is initially given atropine, but his heart rate only increases to 50 beats per minute and he remains hypotensive.

Which of the following is the next best step in the management of this patient's bisoprolol overdose?
a