Download Defibrillation testing should be routinely performed at the time of

Defibrillation testing should be routinely
performed at the time of implantable
cardioverter-defibrillator implantation
Contra
Fernando Arribas
Cardiology Service
Hospital “12 de Octubre”
Madrid Spain
D.O.I.
Honoraria from:
• Boston Scientific
• Medtronic
• St. Jude Medical
• Böhringer Ingelheim
• Merck
• Sanofi Aventis
• Bayer
Declaration of Interest
Institutional funding from:
• Boston Scientific
• Medtronic
• St Jude
G. Klein´s Debaters Rules
 Rephrase the question to suit your argument
 Degrade your opponent whenever possible
 Use anecdotal data abundantly
 Obfuscate data not fitting your hypothesis
 Appeal to non available randomized trials
 Quote Framingham at least once
 Be patronizing to the chairmen
 Appeal to the worst instincts of the audience
 Quote your opponent out of context from previous publications
George Klein email communication, September 2003
Defibrillation testing should be routinely
performed at the time of implantable
cardioverter-defibrillator implantation
adverb
• as a normal part of a job or process
• repeatedly, and unsurprisingly
adjective
• performed as part of a regular procedure
rather than for a special reason
Evidence Based Medicine
A Randomized-Clinical Trial to Assess the Safety and Predictive Value of
Intra-Operative Defibrillation Testing of Implantable Defibrillators
All ICD
and/or CRT
initial
implants
DFT testing
@ implant
R
1:1
no testing
@ implant
Assess
Assess
safety
efficacy
(Am Heart J 2010;159:98-102.)
(J Cardiovasc Electrophysiol, Vol. 19, pp. 400-405, April
2008)
(J Cardiovasc Electrophysiol, Vol. 17, pp. 140-145, February 2006)
What are we testing …
Induced VF: someway different from spontaneous VF
Shock on T or 50 Hz nothing to do with ischaemia, myocardial stress,
Autonomic NS…
Different VF means different probability for defibrilation (DFT)
Spontaneous VF is faster and less organized than induced
Organization correlates with probability for termination
Differences in the activation patterns between sustained and
self-terminating episodes of human ventricular fibrillation.
Mäkikallio TH, Huikuri HV, Myerburg RJ, Seppänen T, Kloosterman M, Interian A Jr, Castellanos A, Mitrani RD.
Ann Med. 2002;34:130-5.
How are we testing DF…
Threshold for stimulation: yes or no
Defibrillation Threshold: probabilistic value
80%
20%
Strickberger SA et al. Circulation 1997;96:1217–
1223.
Marchlinski FE et al. Am J Cardiol 1988;62:393–398.
Neuzner J et al. Am J Cardiol 1999;83:34D–39D.
From DFT to Safety margin:
Successful defibrillation with two shocks – consecutive? – more than
10 J under the maximum energy of the device.
Or even one!
Why are we testing DF? …
Most of implanted ICDs will never treat a VF episode
Appropriate shocks
Average per year
5,1%
Appropriate shocks
8% 1 year
23% 5 Year
Only 30% of patients will receive an appropriated therapy (2-4 y)
Should a ventricular arrhythmia occur, the most probable is VT
VT has a different mechanism and then a different role for ATP
Why are we testing DF? …
Bayesian analysis
The high pre-test probability of success reduces the value of testing
What if negative? Is it a false negative result?
“Good” DFT in 95% of cases
Average DFT for single coil 8-10 J and 10-12 J for double coil
Safety margin > 10J in 97,8 % of cases
Why are we testing DF? …
The test could be not predictive
A percentage of failing energies may defibrilate at a second attempt
7-17% of energies 10-15 J over DFT may fail
Ischemic VF requires higher energy to terminate than induced VF
without ischaemia in animal models
Why are we testing DF? …
The test is not predictive
The first defibrillation shock of 20 J was delivered.
If unsuccessful, a transthoracic rescue shock was
applied. If the first defibrillation attempt at 20 J
was successful, the second defibrillation attempt
was to be performed with a 10-J shock. If the first
attempt of 20 J was unsuccessful, the second
attempt was to be performed with a 30-J shock. No
further VF inductions were recommended
regardless of defibrillation success after the second
induction.
Why are we testing DF? …
The test is not predictive
PACE 2009; 32:573–578
Why are we testing DF? …
DFT is not absolutely safe: risk from VF and from shocks
There were a total of 19,067 ICD implants during the study period.
There were:
3 DFT testing–related deaths
5 DFT testing–related strokes
27 episodes that required prolonged resuscitation
(2 patients had significant clinical sequelae)
DFT was performed in 80% of cases
ICD implant complications
Brignole
Credit
Death
0.07
0
CVA/TIA
0.05
0.6
PE/NCNS-SE
0.02
0.6
MI
0.7
0
CPR/IABP
0.15 + 0.11
0
Simpson
Russo
Birnie
Swerdlow
Ave.
0.35
0.01
0.05
0.03
0.05
0.1
0.18
1.0
0.9
0.5
0.2
Heart Failure
3.6
0.4
1.5
Aspiration, intubation
0
0.1
0.1
Arterial Line
Complication
0
0.4
0.2
ICU stay
9
0.5 /3.6
What about real life …
1997 – 2003
4,7 % no DFT
1996 – 2003
24 % no DFT
2007 – 2010
67 % no DFT
2006 – 2007
36 % no DFT
2008 - 2009
61% no DFT
Methods
The SAFE-ICD study was a multicenter, prospective, longitudinal, observational
study designed to assess the safety of DT performed during the implantation
procedure, and DT strategies in consecutive patients undergoing de novo ICD
insertion. No deviation from the centers’ current practice was introduced by this
study protocol.
Results
Overall, 836 (39%) patients had DT performed during the ICD insertion procedure
and 1,284 (61%) did not.
Safety margin data were available for 695 patients in the DT group: a safety
margin > 10 J was present in 648 (93%) patients and< 10 J in 47 (7%).
Although fairly balanced, DT patients had
less severe underlying structural heart
disease than non DT patients, as evidenced
by lower rate of congestive heart failure,
New York Heart Association functional class
III or IV, atrial fibrillation, higher ejection
fraction, and less usage of diuretics and
digoxin
Defibrillation testing should NOT be
routinely performed at the time of
implantable cardioverter-defibrillator
implantation