Post on 13-Jan-2016
Step by step guide for Synchronised DC Cardioversion
By: Martin GrantStudent no. 40077467
Cardioversion is defined as a “synchronised direct current (DC) discharge, and … does not apply to ventricular defibrillation or to the pharmacologic reversion of arrhythmias.”
It is synchronised to give electrical discharge at the point of the Q or R wave in the ECG cycle.
The reason to synchronise this is to prevent a shock occurring during repolarisation of ventricles in the T wave, which can lead to Ventricular Fibrillation.
What is Cardioversion?1
The ECG
Left shows the various waves throughout the ECG and explains what each deflection means from the isoelectric line.
Right shows another ECG but with colour demonstrates the duration of each different segment.
Fig 1
Fig 2
Based on advanced cardiac life support (ACLS) guidelines, any patient with narrow or wide QRS complex tachycardia (ventricular rate >150) who is unstable (for example, chest pain, pulmonary oedema, lightheaded, hypotension) should be immediately treated with synchronized electrical cardioversion.
Indications2
Supraventricular tachycardia due to re-entry Atrial fibrillation Atrial flutter Atrial tachycardia Monomorphic VT with pulses
Contraindications Digoxin toxicity–associated tachycardia Sinus tachycardia caused by various clinical
conditions Multifocal atrial tachycardia
Also recommended in the following:
Midaxillary line
Important body landmarks
• Right Sternal edge• Intercosta
l spaces
First of all, the appropriate equipment must be organised:◦ IV access◦ Airway management equipment◦ Sedative drugs (midazolam and fentanyl)◦ Cardioversion monitoring device
Procedure
Place patient onto bed Remove upper garments Apply heart tracing leads
Step 1
Conduction strips
Points of application
Leads: Red, Amber, Green (Traffic lights)
Turn the Cardioversion machine on
Step 2
Twist green nozzle clockwise to
activate
Off
Place on the pads
Step 3
Pads and connection for
machine
First pad: 2nd or 3rd intercostal space, Right Sternal edge
Second pad: 4th or 5th Intercostal space ,Midaxillary line
Anterolateral pad positioning
Check heart tracing is being picked up
Step 4
Press Sync to locate R waves
Step 5R waves indicated by arrows
Set the voltage as per guidelines on the condition presenting with the patient
Step 6
WARN EVERYBODY AROUND THE BED YOU ARE ABOUT TO PRESS CHARGE AND SHOCK
Everyone should step back from the patient and the bed
Step 7
Press Charge Then Shock
Step 8
Watch the monitor and see if the Rhythm has returned to normal
If not, this may need to be repeated
Below is a before and after ECG from a patient in AAH with Supraventricular tachycardia resolved using Synchronised DC Cardioversion
Step 9
Pre-Cardioversion ECG
Post-Cardioversion ECG
Synchronised cardioversion when practiced correctly can be a very effective way to correct tachycardia’s.
ACLS guidelines should be followed for when it should be used and at which voltage.
Always check for the contraindications prior to the procedure.
Follow the steps above for the correct way to perform the procedure safely and effectively.
Conclusion
1. Lown B. Defibrillation and cardioversion. Cardiovasc Res. Aug 1 2002;55(2):220-4.
2. [Guideline] Part 5: Electrical Therapies. Automated External Defibrillators, Defibrillation, Cardioversion, and Pacing. Circulation. 2005;112:IV-35-IV-46.
Figures3. http://hyperphysics.phy-astr.gsu.edu/hbase/
biology/imgbio/ecg.gif
References