1. Double Sequential Defibrillation
Wm W. Barrington, MD, FACC, FHRS
Associate Professor Medicine
Chief, Cardiology UPMC Shadyside

2. Presenter Disclosure Information
William W. Barrington, MD FACC FHRS
Double Sequential Defibrillation
FINANCIAL DISCLOSURE:
No relevant financial relationship exists

3. A History Lesson Michel Mirowski, M.D. 1924-1990
I would like to start with a bit of a history lesson. Many of you are too young to remember a world without the Implantable Cardioverter Defibrillator – the ICD that is now widely employed and has been proven to be very effective in saving lives. That technology would not have existed except for this man, Michael Mirowski who after conceiving the idea in 1966 with “off the shelf parts” built the initial prototype in 1969.

4. The first animal implants were performed in 1976.
A History Lesson
The first animal implants were performed in 1976.
The first human implant was in 1980.
The first device was approved by the FDA in 1985.
Even after FDA approval, the devices were not easy to come by.
What else could we do?
First Commercial AICD

5. Tried to induce ventricular tachycardia with PES in “drug free” state.
Serial Drug Testing
Tried to induce ventricular tachycardia with PES in “drug free” state. V A
Here we paced the RV at 600 ms (100 bpm) for 8 beats then put in 2 extrastimuli, the first at 310 ms after the last beat of the drive train and the other 260 ms later. In this case it lead to a wide complex tachycardia with more ventricular signal than atrial signals (AV dissociation) establishing the fact tha we induced VT.
If the patient was inducible we administered an antiarrhythmic drug – often procainamide – and repeated the study.
When “inducible," administered antiarrhythmic drug – and repeated the study.

6. Sometimes the patient became “noninducible.”
Serial Drug Testing
Sometimes the patient became “noninducible.”
Other times, the patient developed VF.
Sustained VT or VF was induced in up to 30% of cases.
In 0.1% of case, the VF was refractory or incessant.

7. Sustained VT or VF induced in ~30% studies.
Serial Drug Testing
In 1994, David Hoch reported on his 3 year experience with 2990 patients and 5450 EP studies1.
Sustained VT or VF induced in ~30% studies.
5 patients failed to convert with single shocks (7-20 attempts).
Sinus rhythm was restored in all 5 with “double sequential shocks” delivered within 0.5 to 4.5 seconds of each other.
How did they do this?
1. Hoch, DH et al. JACC

8. Where did this idea come from?
Sequential shocks
Second
Electrodes
(Base-Apex)
Midline
2ICS
Medial to
1st patch
Right scapula
Apex at Anterior
Axillary line
Standard
Electrodes
Where did this idea come from?

9. Animal Studies
In 1986, Doug Zipes lab at University of Indiana2 investigated the use of sequential shocks to reduce defibrillation threshold in dogs.
A single shock delivered over electrode pairs that encompassed the ventricular septum required significantly less energy.
Double sequential shocks (separated by 1 ms) delivered over 2 pathways, reduced the total energy and peak voltage requirement.
Triple sequential shocks did not offer an advantage over double sequential shocks.
2. Chang MS et. al. JACC (1986) 8; …

10. VF was induced and treated with either: Single shocks or
Animal Studies
In 1994 Richard Kerber3 (Univ of Iowa) published the results from a study performed in closed chest dogs:
VF was induced and treated with either:
Single shocks or
Overlapping sequential shocks delivered by adhesive electrodes placed orthogonal to each other.
The overlapping sequential shocks showed significantly higher rates of successful defibrillation at all energy levels.
3. Kerber RE et. al. Circulation (1994) 89;

11. Internal Defibrillation Studies
George Klein4 studied 12 patients undergoing arrhythmia surgery:
All received both single pulse and sequential pulse defibrillation.
Sequential pulses resulted in higher rates of success at lower energies.
4. Douglas LJ, Klein G et. Al. Circulation (1986) 73;

12. 79 studies reported outcomes of 142,740 patients.
Studies in OHCA
Meta analysis by Comilla Sasson,MD et.al. 5 analyzed the literature from January 1, 1950 through August 21, 2008.
79 studies reported outcomes of 142,740 patients.
The pooled survival to hospital admission rate was 23.4%.
The pooled survival to hospital discharge rate was 7.6%.
The survival to hospital discharge rate has not changed in 3 decades!
5. Sasson C et.al. Circ Cardiovasc Qual Outcomes (2010) 3;63-81

13. 499 VT/VF (shockable rhythm), 12 refractory VF.
Studies in OHCA
Eric Cortez6 reported their experience with double sequential shocks in the Columbus, Ohio metropolitan area:
August 1, 2010 through June 30, 2014,
2428 cases of OHCA,
499 VT/VF (shockable rhythm),
12 refractory VF.
9 had termination of VF with double sequential shocks.
3 of these survived to discharge.
6. Cortez E et. al. Resuscitation (2016)

14. January 7, 2008 through December 31, 2010
Studies in OHCA
Jose Cabanas, MD et. al.7 reported their experience with double sequential shocks in the Wake County North Carolina metropolitan area:
January 7, 2008 through December 31, 2010
10 cases of OHCA treated with double sequential shocks,
7 had termination of VF with double sequential shocks.
3 of had ROSC in the field,
None survived to discharge.
7. Cabanas J et. al. Pre hospital Emergency Care (2015) 19;126-30

15. Electrode Placement
Second
Electrodes
Standard
Electrodes

16. Predictors of successful resuscitation of OHCA:
Where are we today?
Predictors of successful resuscitation of OHCA:
Bystander witnessed arrest,
EMS witnessed arrest,
Bystander CPR,
Shock able rhythm (i.e. VT or VF),
ROSC in the field.
40% of patients with out of hospital cardiac arrest (OHCA) are found in VT/VF.
Only 22% of these patients achieve return of spontaneous circulation (ROSC) in the field.

17. Where are we today?
Maybe we can do better with defibrillation and sequential defibrillation has a role:
Points to consider:
A single shock that encompassed the ventricular septum required less energy for defibrillation,
Double sequential shocks reduced the energy & voltage requirements for defibrillation,
Double sequential shocks delivered over orthogonal electrode pairs had the highest success rates at all energy levels.

18. No uniformly accepted electrode placement.
Where do we go from here?
No uniformly accepted electrode placement.
Right scapula
Apex at Anterior
Axillary line
Standard
Electrodes
for single shock
Second
Electrodes
(Ant-Post)
Midline
2ICS
On back
Left side
Provides coverage of septum and orthogonal 2nd pair

19. Thank You