1. External Cardiac Pacing
HAZHIR HEIDARI BEIGVAND
MBChB, FACEM
Emergency Medicine Specialist
FIROUZABADI HOSPITAL

2. History 1791 Galvani 1892 Duchenne Frog experiments
Resuscitated child (submersion )
One leg electrode, tapped chest with other

3. Zoll 1950’s 1980’s 1st successful TCP and monitor
3cm electrode
120V AC for 2msec
1980’s
80cm2 electrode, 40msec pulse duration
 stimulation threshold x 6
More tolerable = renewed interest
FDA approval 1982

4. Indications Symptomatic Bradycardia
50-100% survival to discharge rates
AMI with certain ECG rhythms
Mobitz type II second-degree AV block
Third-degree heart block
Bilateral BBB
Newly acquired or age-indeterminate LBBB, LBBB and LAFBa, RBBB, and LPFBa
RBBB or LBBB and first-degree AV block

5. Indications Asystole ? Tachyarrythmia Most studies no benefit
Benefit shown for <5min post arrest
2/5 survived neurologically normal
Tachyarrythmia
57-95% termination of VT
4-24% acceleration of VT

6. How To Do It Inform the patient Plug in module Attach pads Set rate 70
Dial up mAmps
Set mode (demand first)
Start
Monitor and adjust as needed

7. Capture Feel the pulse 2nd monitor to determine electrical capture
mechanical capture
2nd monitor to determine electrical capture
Unless monitor blanks out skeletal muscle contraction
Ultrasound

8. Not Capturing
Paced Beat
Native Beat
IABP

9. Current 65-100mA (Unstable patient) 50-70mA (Volunteer)
90% tolerate for 15min
Pain  Current / area (up to 10cm2)

10. Energy 100mA for 20msec = 0.1J Threshold for discomfort 1-2J
(with normal TTR, 50 Ohm)
Threshold for discomfort 1-2J
(Skin tingling)
Does not damage the myocardium

11. Discomfort Skeletal muscle contraction is the cause
Often the limiting factor
Attempt AP placement to minimise
Left scapula and midline chest
Use lowest effective current
Sedation as needed
CPR is safe!

12. Muscle Contraction

13. Haemodynamics Cardiac arrest and CHB Sinus
Comparable to transvenous pacing
Sinus
Reduced cardiac output
No ‘atrial kick’ (atrial capture threshold too high)

14. References
Bocka JJ eMedicine
Updated 2002 April 24, excellent summary article
Bocka JJ Ann Emerg Med 1989 Dec; 18(12):1280-6
Hedges JR Pacing Clin Electrophysiol Oct;14(10):1473-8
Barthell E Ann Emerg Med 1988 Nov;17(11):1221-6
Klumbies A Z Gesamte Inn Med 1988 Jul 1;43(13):