Defibrillation threshold testing should no longer be performed: contra

Transcription

1 Defibrillation threshold testing should no longer be performed: contra Andreas Goette St. Vincenz-Hospital Paderborn Dept. of Cardiology and Intensive Care Medicine Germany No conflict of interest to disclose

2 DFT testing Factors that Influence the DFT ICD-System-Specific Factors: Defibrillation electrode size, shape, and surface area Active can Subcutaneous electrode or array Defibrillation electrode location (including right or left-sided pectoral implant) Single vs. dual-coil leads Shock waveform and polarity Patient-Specific Factors: Left ventricular ejection fraction, size, and mass Congestive Heart failure class Gender Body surface area Ischemia Type of underlying heart disease (e.g., hypertrophic cardiomyopathy) Drugs (e.g., amiodarone)

3 DFT testing Factors that Influence the DFT ICD-System-Specific Factors: Defibrillation electrode size, shape, and surface area Active can Subcutaneous electrode or array Defibrillation electrode location (including right or left-sided pectoral implant) Single vs. dual-coil leads Shock waveform and polarity Are several thousand research papers and studies Patient-Specific Factors: Left ventricular ejection fraction, size, and mass Congestive not Heart true failure class or important anymore?! Gender Body surface area Ischemia Type of underlying heart disease (e.g., hypertrophic cardiomyopathy) Drugs (e.g., amiodarone)

4 DFT testing Factors that Influence the DFT ICD-System-Specific Factors: Defibrillation electrode size, shape, and surface area Active can Subcutaneous electrode or array Defibrillation electrode location (including right or left-sided pectoral implant) Single vs. dual-coil leads Shock waveform Do we and have polarity a large, prospective, randomized trial, Patient-Specific Factors: Left ventricular which ejection shows fraction, that size, and no mass DFT testing Congestive Heart failure class Gender is an appropriate strategy? Body surface area Ischemia Type of underlying heart disease (e.g., hypertrophic cardiomyopathy) Drugs (e.g., amiodarone)

5 ICD Trials - Primary prophylaxis ns VT MADIT I DEFINITE SCD-HeFT DINAMIT CAT MUSTT High risk no VA LV-EF (%) MADIT II CABG-Patch

6 DFT testing: retrospective data Viskin and Rosso. Heart Rhythm 2008

7 DFT testing: retrospective data Complications associated with defibrillation threshold testing: The Canadian experience David Birnie, MD,* Stanley Tung, MD, Christopher Simpson, et al. Deaths There were three DFT-related deaths/19,067 cases, indicating an incidence of 0.016%. DFT testing is a misnomer as most centers in Canada now perform an abbreviated protocol (one or two shocks) looking for a defibrillation safety margin15 of 10 J. We do not have details of the DFT testing protocols. Birnie et al. Heart Rhythm 2008

8 DFT testing: positive data Defibrillation Testing at the Time of ICD Insertion: An Analysis from the Ontario ICD Registry. Healey JS, Birnie DH, Lee DS, Krahn AD, on behalf of the Ontario ICD Database Investigators. Conclusions: DT was not associated with an increased risk of perioperative complications. Healey et al. J Cardiovasc Electrophysiol 2010

9 DFT testing: retrospective data

10 DFT testing: retrospective data

11 No Benefit From Defibrillation Threshold Testing in the SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) Baseline DFT data were available for 717 patients (88.4%). All 717 patients had a DFT of 30 J, the maximum output of the device in this study. The DFT was 20 J in 97.8% of patients. There was no survival difference between patients with a lower DFT (10 J, n 547) and a higher DFT (10 J, n 170) (p 0.41). First shock efficacy was 83.0% for the first clinical ventricular tachyarrhythmia event; there were no differences in shock efficacies when the cohort was subdivided by baseline DFT. Although we observed first shock failure in approximately 20% of patients, this was only fatal in 3 patients, all of whom were hospitalized at the time for progressive heart failure. Blatt et al. JACC 2008

12 No Benefit From Defibrillation Threshold Testing in the SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) Although we observed first shock failure in approximately 20% of patients, this was only fatal in 3 patients, all of whom were hospitalized at the time for progressive heart failure. What happens to the implanting physician if a patients dies due to ineffective shocks after no DFT testing? (legal issue)

13 DFT testing: positive data Russo et al. Heart Rhythm (2005)

14 DFT testing: positive data The major finding of our study is that, in an unselected large population of patients undergoing ICD placement, an inadequate safety margin for defibrillation may occur in 6% of patients. Russo et al. Heart Rhythm (2005)

15 DFT testing: secondary prevention Conolly et al. Eur Heart J (2000)

16 DFT testing Defibrillation Threshold Testing in Patients with Hypertrophic Cardiomyopathy Conclusions: Our results suggest that patients with HCM have higher DFTs than patients implanted with ICDs for other indications. More importantly, a higher percentage of HCM patients have DFTs >/= 20 J and the DFT increases with increasing left ventricle wall thickness. These data suggest that DFT testing should always be considered after implanting ICDs in HCM patients. Roberts et al. Pacing Clin Electrophysiol. 2010

17 DFT testing: positive data Defibrillation Threshold Testing (DFT) in a Naturalistic Practice Results of the ALTITUDE Study Michael Cao et al. Heart Rhythm 2010 Introduction: This observational study is designed to address prospectively defined questions utilizing de-identified data obtained from the Boston Scientific ALTITUDE remote monitoring system. We sought to determine the incidence of DFT testing in naturalistic practice settings and to determine if DFT testing predicts first spontaneous shock success for tachycardia events treated in the VF detection zone. Methods: We analyzed data from ICD and CRT-D pts stored EGM episodes prior to first shock VF therapy were available for review in pts. We randomly sampled 2000 pts with a total of 5279 shock episodes between 6/2001-7/2008 according to a statistical plan. An adjudication committee reviewed all EGM's. Results: A total of 270 pts experienced VF with shock as a first therapy (mean age 64 ± 13 years, 79% male, follow-up 38.7 ± 20 months). 87% of ICD and CRT-D pts underwent DFT testing. First shock success for arrhythmias detected in the VF zone was not significantly higher for ICD or CRTD pts having DFT testing compared to those that did not. First shock energy was programmed lower in pts when a DFT testing was performed. Conclusions: In the largest pt cohort reported to date, DFT testing in naturalistic EP practices throughout the U.S is high. While DFT testing does not appear to influence first shock success for terminating VF, it does result in lower energy first shock programming energies. This lower programmed energy may result in a faster delivery of therapy lowering the likelihood of syncope during VF events and may also result in a beneficial prolongation of device longevity.

18 Defibrillation Energy & Myocardial Injury Hurst et al. JACC 1999

19 Defibrillation Energy & Myocardial Injury Hurst et al. JACC 1999

20 Defibrillation Energy & Myocardial Injury Hurst et al. JACC 1999

21 DFT testing: positive data..there are reasons to perform shock testing: - identifying lead dysfunction, - demonstrating appropriate sensing, - testing system integrity to detect the case of device failure. At the present time, we believe the balance of considerations still tilts in favor of shock testing. It remains to be seen if newer devices and more data will tilt the balance in the other direction. Ideker et al. Heart Rhythm (2005)

22 DFT testing is important! DFT testing is important to rule out ICD malfunction/undersensing. DFT testing has no negative effects on mortality. To reproduce the positive trial data (secondary prevention, HCM!) Are high energy shock ICDs really not harmful in longterm? Retrospective data and meta-analyses are hypothesis generating but no true evidence! Idea of no DFT testing has to be evaluated in large prospective trials! It is way too early to recommend no DFT testing in all patients and in all Institutions.

23 Thank you!

24 DFT testing is important! The physician has to prove that the implant procedure was correct and the device had no malfunction! The DFT testing does not harm the patient! Thus, DFT testing is important to let the patient and the physician sleep well at night!

25 ICD 1 0 Prevention Trial CABG-Patch Results Hazard Ratio CAD, MI MUSTT MADIT I MADIT II CAD, NICM NICM DINAMIT SCD-HeFT DEFINITE AMIOVIRT CAT ICD better No ICD better