Complications associated with defibrillation threshold testing: The Canadian experience

doi:10.1016/j.hrthm.2007.11.018

Heart Rhythm

Volume 5, Issue 3, March 2008, Pages 387-390

https://doi.org/10.1016/j.hrthm.2007.11.018 Get rights and content

Background

Defibrillation threshold (DFT) testing has traditionally been a routine part of implantable cardioverter-defibrillator (ICD) implantation, despite a lack of compelling evidence that it predicts or improves outcomes. In the past, when devices were much less reliable, DFT testing seemed prudent; however, modern ICD systems have such a high rate of successful defibrillation that many electrophysiologists now question whether DFT testing is still worthwhile, particularly since DFT testing may now be the highest acute risk component of ICD implantation.

Objective

The purpose of this study was to systematically document complications directly attributable to intraoperative DFT testing.

Methods

We obtained data on DFT-related complications from all 21 adult ICD implant centers in Canada, covering the period from January 1, 2000, to September 30, 2006.

Results

There were a total of 19,067 ICD implants in Canada during the study period. There were three DFT testing–related deaths, five DFT testing–related strokes, and 27 episodes that required prolonged resuscitation. Two patients had significant clinical sequelae after prolonged resuscitation.

Conclusions

The risk of severe complications from intraoperative DFT testing appears small, even allowing for the underestimation of its true rate with the current study methodology. These slight but measurable risks must be considered when assessing the risk-benefit ratio of the procedure. Additional data from ongoing prospective ICD registries and/or clinical trials are required.

Section snippets

Methods

All 21 adult ICD implant centers in Canada were approached to collaborate. The study period was defined as January 1, 2000, to September 30, 2006. Incidence and details of the following major complications were collated:

1
Death: death from any cause that was felt to be related to DFT testing.
2
Cerebrovascular accident or transient ischemic attack (CVA/TIA) within 24 hours of DFT testing.
3
Prolonged resuscitation: requirement for external cardiac massage and/or more than one external rescue shock(s)

ICD implants and DFT testing

All 21 adult ICD centers agreed to participate and provided full data for the entire study period.

There were a total of 19,067 ICD implants (de novo and generator changes) in Canada between January 1, 2000, and September 30, 2006. In 2005, there were 480 ICD implants in Ontario, and 384/480 (80%) had DFT testing at the time of implant.

Deaths

There were three DFT-related deaths/19,067 cases, indicating an incidence of 0.016%.

Case 1

Case 1 is a 52-year-old man with nonischemic cardiomyopathy (CM) and an ICD

Discussion

We believe that this is the first large series evaluating the risk of major complications associated with peri-implant DFT testing. There were a total of 19,067 ICD implants (de novo and generator changes) in Canada during the study period. There were three DFT testing–related deaths (0.016%), five DFT testing–related strokes (0.026%), and 27 episodes of prolonged resuscitation (0.14%). Two patients had significant sequelae from their prolonged resuscitation.

There have been previous reports of

References (15)

A.M. Russo et al.
Defibrillation threshold testing: is it really necessary at the time of implantable cardioverter-defibrillator insertion?
Heart Rhythm
(2005)
C. Kolb et al.
Near-fatal incident on routine induction of ventricular fibrillation at the replacement of an implantable cardioverter defibrillator
Int J Cardiol
(2006)
K.M. Stein et al.
Effect of transthoracic shocks on left ventricular function
Resuscitation
(2005)
G. Steinbeck et al.
Hemodynamic deterioration during ICD implant: predictors of high-risk patients
Am Heart J
(1994)
J.A. Joglar et al.
Effects of repeated electrical defibrillations on cardiac troponin I levels
Am J Cardiol
(1999)
R.E. Ideker et al.
Should shocks still be administered during implantable cardioverter-defibrillator insertion?
Heart Rhythm
(2005)
S.A. Strickberger et al.
Is defibrillation testing required for defibrillator implantation?
J Am Coll Cardiol
(2004)

There are more references available in the full text version of this article.

Cited by (145)

Humerus fracture during unsuccessful induction of ventricular fibrillation for subcutaneous implantable cardioverter-defibrillator testing
2024, HeartRhythm Case Reports
Predictive value of the PRAETORIAN score for defibrillation test success in patients with subcutaneous ICD: A subanalysis of the PRAETORIAN-DFT trial
2024, Heart Rhythm
The PRAETORIAN score estimates the risk of failure of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy by using generator and lead positioning on bidirectional chest radiographs. The PRospective randomized compArative trial of subcutanEous implanTable cardiOverter-defibrillatoR ImplANtation with and without DeFibrillation Testing (PRAETORIAN-DFT) investigates whether PRAETORIAN score calculation is noninferior to defibrillation testing (DFT) with regard to first shock efficacy in spontaneous events.
This prespecified subanalysis assessed the predictive value of the PRAETORIAN score for defibrillation success in induced ventricular arrhythmias.
This multicenter investigator-initiated trial randomized 965 patients between DFT and PRAETORIAN score calculation after de novo S-ICD implantation. Successful DFT was defined as conversion of induced ventricular arrhythmia in <5 seconds from shock delivery within 2 attempts. Bidirectional chest radiographs were obtained after implantation. The predictive value of the PRAETORIAN score for DFT success was calculated for patients in the DFT arm.
In total, 482 patients were randomized to undergo DFT. Of these patients, 457 (95%) underwent DFT according to protocol, of whom 445 (97%) had successful DFT and 12 (3%) had failed DFT. A PRAETORIAN score of ≥90 had a positive predictive value of 25% for failed DFT, and a PRAETORIAN score of <90 had a negative predictive value of 99% for successful DFT. A PRAETORIAN score of ≥90 was the strongest independent predictor for failed DFT (odds ratio 33.77; confidence interval 6.13–279.95; P < .001).
A PRAETORIAN score of <90 serves as a reliable indicator for DFT success in patients with S-ICD, and a PRAETORIAN score of ≥90 is a strong predictor for DFT failure.
Sudden Cardiac Death at Home: Potential Lives Saved With Fully Automated External Defibrillators
2024, Annals of Emergency Medicine
Sudden cardiac death from ventricular arrhythmia kills about 350,000 people annually in the United States. This number has not improved since the widespread public availability of semi-automated external defibrillators (AEDs) and the teaching of nonbreathing cardiopulmonary resuscitation (CPR) procedures. When an out-of-hospital cardiac arrest occurs in a public space, lay witnesses do CPR in 40% of the cases and use AEDs on only 7.4% of the victims before emergency medical services (EMS) arrive. About 70% of sudden cardiac death occurs at home, where an AED is usually unavailable until EMS appears. The time from a 911 call to shock averages approximately 7 minutes in urban areas and is more than 14.5 minutes in rural environments. Because arrest onset is often not observed, arrest onset to shock times maybe even longer. Survival from cardiac arrest decreases by approximately 7 to 10% per minute of ventricular arrhythmia. A prearrest protocol is proposed for the at-home use of fully automated external defibrillators in select cardiac patients, which should reduce the arrest-to-shock interval to under 1 minute and may eliminate the need for CPR in some cases.
An in-silico assessment of efficacy of two novel intra-cardiac electrode configurations versus traditional anti-tachycardia pacing therapy for terminating sustained ventricular tachycardia
2021, Computers in Biology and Medicine
The implanted cardioverter defibrillator (ICD) is an effective direct therapy for the treatment of cardiac arrhythmias, including ventricular tachycardia (VT). Anti-tachycardia pacing (ATP) is often applied by the ICD as the first mode of therapy, but is often found to be ineffective, particularly for fast VTs. In such cases, strong, painful and damaging backup defibrillation shocks are applied by the device. Here, we propose two novel electrode configurations: “bipolar” and “transmural” which both combine the concept of targeted shock delivery with the advantage of reduced energy required for VT termination. We perform an in silico study to evaluate the efficacy of VT termination by applying one single (low-energy) monophasic shock from each novel configuration, comparing with conventional ATP therapy. Both bipolar and transmural configurations are able to achieve a higher efficacy (93% and 85%) than ATP (45%), with energy delivered similar to and two orders of magnitudes smaller than conventional ICD defibrillation shocks, respectively. Specifically, the transmural configuration (which applies the shock vector directly across the scar substrate sustaining the VT) is most efficient, requiring typically less than 1 J shock energy to achieve a high efficacy. The efficacy of both bipolar and transmural configurations are higher when applied to slow VTs (100% and 97%) compared to fast VTs (57% and 29%). Both novel electrode configurations introduced are able to improve electrotherapy efficacy while reducing the overall number of required therapies and need for strong backup shocks.
Defibrillation failure with an electrical short circuit caused by internal insulation breach
2021, HeartRhythm Case Reports
The subcutaneous implantable cardioverter defibrillator in 2019 and beyond
2020, Trends in Cardiovascular Medicine
The completely subcutaneous implantable cardioverter defibrillator (S-ICD) is rapidly evolving to become a complete alternative for the transvenous ICD (TV-ICD) leaving the heart and vasculature untouched. Newer trials and registries in cohorts that are similar to real-world ICD patient populations confirm the initial data on safety and efficacy. Technical improvements have resulted in reduced inappropriate shock rates, although more data are warranted, and new developments such as substernal lead positioning, communication between the S-ICD and a leadless cardiac pacemaker and remote monitoring options have evolved to overcome the shortcomings of S-ICD therapy. With these continuing developments, it is expected that within the next years the S-ICD will continue to evolve to a treatment option for ventricular arrhythmia as effective as the TV-ICD overcoming the shortcomings of transvenous leads as well as the drawbacks of the initial system, providing effective shock therapy, pacing capabilities, low complication and inappropriate therapy rates, and automated remote monitoring.

View all citing articles on Scopus

: Dr. C. Simpson, Dr. F. Philippon Dr. D. Birnie, Dr. A. Krahn, and Dr. J. Healey have received research grants/support from Boston Scientific. Dr. D. Birnie, Dr. F. Philippon, Dr. D. Exner, and Dr. C. Simpson have received research grants/support from Medtronic. Dr. D. Exner and Dr. F Philippon have received research grants/support from St. Jude. Dr. D. Exner has received research grants/support from GE Healthcare, and Dr. C. Simpson has received research grants/support from Sorin Group. Dr. D. Exner, Dr. C. Simpson, Dr. R. Parkash, and Dr. F. Philippon have received honoraria from Medtronic. Dr. D. Exner and Dr. R. Parkash have received honoraria from St. Jude. Dr. D. Exner has received honoraria from GE Healthcare, and Dr. C. Simpson has received honoraria from Boston Scientific. Dr. D. Exner, Dr. D. Birnie, Dr. S. Kimber, and Dr. F. Philippon have received speakers’ fees from Medtronic. Dr. S. Kimber has received speakers’ fees from St. Jude and Guidant. Dr. D. Exner and Dr. F. Philippon have received speakers’ fees from GE Healthcare and St. Jude. Dr. F. Ayala-Paredes has received speakers’ fees from Biotronic. Dr. D. Exner has served as a consultant for Medtronic and GE Healthcare. Dr. F. Ayala-Paredes has served as a consultant for Biotronic, and Dr. F. Philippon has served as a consultant for Boston Scientific. The remaining authors report no conflicts.

View full text

Original-clinicalComplications associated with defibrillation threshold testing: The Canadian experience

Background

Objective

Methods

Results

Conclusions

Section snippets

Methods

ICD implants and DFT testing

Deaths

Case 1

Discussion

Heart Rhythm

Int J Cardiol

Resuscitation

Am Heart J

Am J Cardiol

Heart Rhythm

J Am Coll Cardiol

Original-clinical
Complications associated with defibrillation threshold testing: The Canadian experience