Causes

• Cardiac: Heart Block, Myocardial infarction, Myocarditis
• Metabolic: Hypothermia, Hyperkalaemia, Hypokalaemia, Hypothyroid, Hypoxia
• Toxin: digoxin, B-blocker

Treatment

For ALL conditions leading to bradycardia treating the underlying condition is the most appropriate treatment and for some the only thing that will work (i.e. severe hypothermia)

However, for some patients you may need to consider using the treatments outlined below, as a bridge to treating the cause (e.g. awaiting pacemaker)

Atropine

This is the most common initial agent used, and is often started pre-hospital by the ambulance crew. Normally given I.V. in 500μg boluses up to a total of 3mg (3000μg)

Contraindication is Acute Glaucoma

Isoprenaline

If Atropine fails or is contraindicated, Isoprenaline (a non-selective B-adrenoceptor agonist) is used as an alternative. It is a I.V. infusion which is titrated to effect – Algorithm here (latest available form cardiology)

External Pacing

**Remember this is painful so the patient may require some sedation**

Indication of external pacing

• Signs of Pump Failure: Shock (SBP <90mmHg), Pulmonary Oedema, Confusion, Cardiac Chest Pain
• Failure of medication
• Overdrive pacing

Connection

Defib Pads: the pads can be attached Anterior-Posterior (1st choice) OR Anterior-Laterally. [N.B. if pacing is failing to capture, it is worth alternating position]

Chest Leads: when pacing or cardioverting the patient should also be connected to the Defib via the chest leads. The Defib can’t monitor and shock reliably through the pads only.

 

Starting Pacing

Once connected to the Defib:

1. Select “Pacer”

2. Select “Pacer Rate”, use the arrows (3) to adjust the rate typically 30bpm over the initial rate.

4. Select  “Power Output”, use the arrows (3) to select 70mA to begin.

5. Select “Start Pacing”

 

Capture

Once pacing is started you need to adjust the “Power Output” (4), using the arrows (3) to find the minimum power needed to achieve capture (this may be greater or less than 70mA).

“Capture” will be demonstrated by an organised QRS with each pacing impulse & a corresponding pulse (the most common reason for capture to fail is low “Power Output”)

Once the minimum capture power is found set the pacer at 10mA above that.

“Pacer Rate” can then also be adjusted to achieve the best clinical effect.

 

Internal Pacing

For some external pacing doesn’t work, and internal pacing is our only option. Ideally the patient will go to Cath-Lab (CRH). However, if needs must Cardiology have come to ED and placed temporal wires when needed.