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Pope MTB, Paisey JR, Roberts PR. Defibrillation Threshold Testing for Right-sided Device Implants: A Review to Inform Shared Decision-making, in Association with the British Heart Rhythm Society. Arrhythm Electrophysiol Rev 2023; 12:e10. [PMID: 37427305 PMCID: PMC10326664 DOI: 10.15420/aer.2022.38] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/27/2022] [Indexed: 07/11/2023] Open
Abstract
Prevention of sudden death using ICDs requires the reliable delivery of a high-energy shock to successfully terminate VF. Until more recently, the device implant procedure included conducting defibrillation threshold (DFT) testing involving VF induction and shock delivery to ensure efficacy. Large clinical trials, including SIMPLE and NORDIC ICD, have subsequently demonstrated that this is unnecessary, with a practice of omitting DFT testing having no impact on subsequent clinical outcomes. However, these studies specifically excluded patients requiring devices implanted on the right side, in whom the shock vector is significantly different and smaller studies suggest a higher DFT. In this review, the data regarding the use of DFT testing, focusing on right-sided implants, and the results of a survey of current UK practice are presented. In addition, a strategy of shared decision-making when it comes to deciding on the use of DFT testing during right-sided ICD implant procedures is proposed.
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Affiliation(s)
- Michael TB Pope
- Department of Cardiology, Royal Bournemouth Hospital, Bournemouth, UK
| | - John R Paisey
- Department of Cardiology, University Hospitals Southampton NHS Foundation Trust, Southampton, UK
| | - Paul R Roberts
- Department of Cardiology, University Hospitals Southampton NHS Foundation Trust, Southampton, UK
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Siddiqi N, Tchou P, Niebauer MJ, Wilkoff BL, Varma N. Influence of "high" defibrillation thresholds on patient survival and impact of system modification. J Cardiovasc Electrophysiol 2021; 33:234-240. [PMID: 34911148 DOI: 10.1111/jce.15326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/20/2021] [Accepted: 10/20/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To test whether a high defibrillation threshold (DFT) marks patients with poor outcomes which are improved when DFT is decreased by system modification (subcutaneous coil implant; SM). BACKGROUND The electrical substrate generating fast ventricular arrhythmias may generate poor outcomes among patients treated with implantable cardioverter-defibrillators (ICDs), even when arrhythmias are treated successfully. Since patients with high DFTs have increased mortality, we contrasted survival among patients with high DFT treated with and without SM. METHODS We studied consecutive patients undergoing ICD implantation and DFT testing at Cleveland Clinic over a 14-year period. High DFT was defined as successful defibrillation by shock strength >25 J or ≤10 J of maximal device output. Mortality was recorded using the Social Security Death Index. Survival was compared among those high DFT patients receiving SM versus the remainder. RESULTS Out of 6353 patients tested, 191 (3%) had high DFT (32.1 ± 3.7 J) versus 13.9 ± 4.9 J in the remainder ("acceptable DFT," p < .001). One hundred twenty-one high DFT patients (63%; 33.3 ± 3.4 J) underwent SM, which significantly decreased DFT (24.8 ± 5.9 J; p < .001). Seventy patients (37%; 30.3 ± 3.3 J) did not undergo SM. During follow-up, 38% (2363/6162; 7.8 yrs) patients with acceptable DFT died versus 48% high DFT patients (91/191; 5.6 yrs.; p < .001). Concomitantly, 48% patients with SM (58/121) died, as compared to 47% patients (33/70) without SM (p = .91); median follow-up 4.9 yrs). CONCLUSION Patients with high DFT have a higher mortality than those with acceptable DFT. The additional subcutaneous coil implant decreases DFT to an acceptable range but does not appear to improve survival. The electrical substrate underlying high DFT appears to determine survival.
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Affiliation(s)
- Najmul Siddiqi
- Department of Cardiovascular Medicine, Cleveland Clinic, Section of Cardiac Pacing and Electrophysiology, Cleveland, Ohio, USA
| | - Patrick Tchou
- Department of Cardiovascular Medicine, Cleveland Clinic, Section of Cardiac Pacing and Electrophysiology, Cleveland, Ohio, USA
| | - Mark J Niebauer
- Department of Cardiovascular Medicine, Cleveland Clinic, Section of Cardiac Pacing and Electrophysiology, Cleveland, Ohio, USA
| | - Bruce L Wilkoff
- Department of Cardiovascular Medicine, Cleveland Clinic, Section of Cardiac Pacing and Electrophysiology, Cleveland, Ohio, USA
| | - Niraj Varma
- Department of Cardiovascular Medicine, Cleveland Clinic, Section of Cardiac Pacing and Electrophysiology, Cleveland, Ohio, USA
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Kim SS, Park HW, Jeong HK, Lee KH, Yoon NS, Cho JG. Defibrillation threshold testing during implantable cardioverter defibrillator implantation: 5-year follow-up. J Interv Card Electrophysiol 2020; 60:485-491. [PMID: 32399866 DOI: 10.1007/s10840-020-00733-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/16/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE Defibrillation threshold (DFT) testing is a routine practice in some Asian countries for patients receiving an implantable cardioverter defibrillator (ICD). However, there are few long-term data about the necessity of intraoperative DFT testing in an Asian population. We investigated the safety of DFT testing and the long-term clinical outcomes in Asian patients undergoing ICD implantation. METHODS All patients undergoing de novo transvenous ICD implantation were randomized to undergo periprocedural DFT testing. The study included 67 patients (50 males; 51.5 ± 16.9 years) who underwent ICD implantation with (n = 33) or without (n = 34) intraoperative DFT testing between March 2012 and February 2014. We compared first-shock success, composite safety end points (the sum of complications recorded at 30 days), arrhythmic death, and all-cause mortality. RESULTS The baseline clinical characteristics and the procedural-related adverse event rate (3.0% with DFT vs. 0% with non-DFT, p = 0.214) did not differ between groups. The programmed output of the first shock was lower in the DFT testing group (22.9 ± 4.4 J vs. 25.3 ± 5.4 J, p = 0.007). However, there were no significant differences between groups for all-cause mortality (12.1% vs. 17.6%, p = 0.526) or first-shock success rate for ventricular arrhythmia (100% vs. 88.2%, p = 0.471). CONCLUSIONS There were no between-group differences in periprocedural safety, complications, and long-term clinical outcomes. Our results suggest that DFT testing in Asian patients allows reduction of the programmed output of the first shock, but does not affect long-term clinical outcomes.
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Affiliation(s)
- Sung Soo Kim
- Cardiovascular Division, Chosun University Hospital, 365, Pilmun daero, Dong-gu, Gwangju, South Korea
| | - Hyung Wook Park
- Department of Cardiovascular Medicine, Chonnam National University Medical School, 42, Jebong-ro, Dong-gu, Gwangju, 61469, South Korea.
| | - Hyung Ki Jeong
- Department of Cardiovascular Medicine, Chonnam National University Medical School, 42, Jebong-ro, Dong-gu, Gwangju, 61469, South Korea
| | - Ki Hong Lee
- Department of Cardiovascular Medicine, Chonnam National University Medical School, 42, Jebong-ro, Dong-gu, Gwangju, 61469, South Korea
| | - Nam Sik Yoon
- Department of Cardiovascular Medicine, Chonnam National University Medical School, 42, Jebong-ro, Dong-gu, Gwangju, 61469, South Korea
| | - Jeong Gwan Cho
- Department of Cardiovascular Medicine, Chonnam National University Medical School, 42, Jebong-ro, Dong-gu, Gwangju, 61469, South Korea
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Abstract
When the transvenous ICD initially came into use for primary and secondary prevention of sudden cardiac death, defibrillation threshold (DFT) testing was universally performed. However, DFT testing is no longer routinely recommended for transvenous ICD implantation except in certain situations. Risk scores can help guide the decision to perform DFT testing. The subcutaneous ICD represents an area of uncertainty, with limited data available regarding the role of DFT testing in these devices. Current guidelines give a class I recommendation for performing DFT testing at the time of implant. Further studies are needed before this recommendation can be safely dismissed.
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Affiliation(s)
- Justin Hayase
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA Los Angeles, CA, USA
| | - Duc H Do
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA Los Angeles, CA, USA
| | - Noel G Boyle
- UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA Los Angeles, CA, USA
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Duffett S, El Hajjaji I, Manlucu J, Yee R. Implantable Cardioverter Defibrillator Implantation with or Without Defibrillation Testing. Card Electrophysiol Clin 2018; 10:119-25. [PMID: 29428133 DOI: 10.1016/j.ccep.2017.11.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Defibrillation testing (DFT) during implantable cardioverter-defibrillator (ICD) implantation is still considered standard of care in some, but in increasingly fewer centers. The goal is to ensure that the device system functions as intended by testing in the controlled laboratory setting. Although safe, complications can occur and DFT is associated with an increased procedural time and cost. DFT is useful in assessing device function when programming changes or patient characteristics raise concerns regarding ICD efficacy. DFT remains standard of practice following implantation of subcutaneous ICDs and other specific circumstances. Implanting physicians should remain familiar with the process of DFT and situations where it is useful for individual patients.
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Al-Ghamdi B, Shafquat A, Alruwaili N, Emmanual S, Shoukri M, Mallawi Y. Subcutaneous Implantable Cardioverter Defibrillators Implantation Without Defibrillation Threshold Testing: A Single Center Experience. Cardiol Res 2017; 8:319-326. [PMID: 29317975 PMCID: PMC5755664 DOI: 10.14740/cr638w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/01/2017] [Indexed: 11/26/2022] Open
Abstract
Background Subcutaneous implantable cardioverter defibrillator (S-ICD) system has been proven to be an effective therapy for prevention of sudden cardiac death (SCD) in selected patients. Although the Shockless IMPLant Evaluation (SIMPLE) trial has shown that defibrillation threshold (DFT) testing is not necessary for transvenous ICD (TV-ICD) systems, it is still recommended for S-ICD systems. We aimed to study the efficacy and safety of S-ICD implantation without DFT in our Heart Center with the comparison of S-ICD patients’ outcome to those with a single chamber TV-ICD without DFT in the same period. Methods A retrospective analysis of patients underwent S-ICD without DFT from December 2014 to May 2016 with the comparison to single chamber TV-ICD patients implanted during the same period. Results Thirty consecutive patients (23 males (76.7%); mean age 41 ± 13 years; mean left ventricular ejection fraction 30±12%) received a S-ICD for primary (25 patients, 83.3%) or secondary prevention (five patients, 16.7%) of SCD. During a mean follow-up of 710.6 ± 190 days, three patients received 38 appropriate ICD shocks (90.5%), and two patients received four inappropriate shocks (9.5%). There were two mortalities (6.7%): one cardiac and one non-cardiac. When compared to 30 consecutive who received a single chamber TV-ICD during the same period, there was no significant difference in mortality. Conclusions Implantation of S-ICD using intermuscular approach without DFT seems to be safe and effective. Data from large S-ICD registries with long-term follow-up, and preferably randomized controlled studies, are needed to confirm this finding.
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Affiliation(s)
- Bandar Al-Ghamdi
- Heart Center, King Faisal Specialist Hospital & Research Centre, Zahrawi St, Al Maather, Riyadh 12713, Saudi Arabia.,Alfaisal University, Riyadh, Saudi Arabia
| | - Azam Shafquat
- Heart Center, King Faisal Specialist Hospital & Research Centre, Zahrawi St, Al Maather, Riyadh 12713, Saudi Arabia.,Alfaisal University, Riyadh, Saudi Arabia
| | - Nadiah Alruwaili
- Heart Center, King Faisal Specialist Hospital & Research Centre, Zahrawi St, Al Maather, Riyadh 12713, Saudi Arabia
| | - Shisamma Emmanual
- Heart Center, King Faisal Specialist Hospital & Research Centre, Zahrawi St, Al Maather, Riyadh 12713, Saudi Arabia
| | - Mohamed Shoukri
- Cell Biology Department, King Faisal Specialist Hospital & Research Centre, Zahrawi St, Al Maather, Riyadh 12713, Saudi Arabia.,Alfaisal University, Riyadh, Saudi Arabia
| | - Yaseen Mallawi
- Heart Center, King Faisal Specialist Hospital & Research Centre, Zahrawi St, Al Maather, Riyadh 12713, Saudi Arabia
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Hayase J, Boyle NG. Defibrillation Testing During ICD Implantation - Should we or Should we Not? J Atr Fibrillation 2017; 9:1508. [PMID: 29250267 PMCID: PMC5673383 DOI: 10.4022/jafib.1508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 11/30/2016] [Accepted: 01/23/2017] [Indexed: 11/10/2022]
Abstract
The implantable cardioverter defibrillator (ICD) is an established therapy for improving mortality for primary and secondary prevention of sudden cardiac death. Whether to perform defibrillation threshold testing (DFT) either intraoperatively or post-operatively remains a controversial issue. The DFT is defined as the minimum energy required at which two shocks can successfully terminate ventricular fibrillation and dates from the era of surgically implanted devices with epicardial patches. Typically, a safety margin of at least 10J is employed for device programming, though some trial data suggest that a margin of 5J could be just as effective. Various methods have been utilized to perform DFT testing, and no particular method has been shown to be superior to another [Figure 1]. Previously, guideline recommendations addressed the indications for ICD implantation but did not comment on DFT testing. Recent consensus statements now provide some guidance as to when it is appropriate to perform or not perform DFT testing in light of new trial data. This review will address some of the risk factors for having a higher DFT, impact of DFT testing on patient outcomes, and some of the risks and contraindications of DFT testing.
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Affiliation(s)
- Justin Hayase
- UCLA Cardiac Arrhythmia Center, UCLA Health System,David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Noel G Boyle
- UCLA Cardiac Arrhythmia Center, UCLA Health System,David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Liu X, Asirvatham S, Kabell GG. Orthostatic increase in defibrillation threshold leading to defibrillation failure and prolonged cardiac arrest in a sitting position: Lessons from a patient’s near-fatal experience. HeartRhythm Case Rep 2016; 2:313-317. [PMID: 28491699 PMCID: PMC5419841 DOI: 10.1016/j.hrcr.2016.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Xiaoke Liu
- Division of Cardiology, Borgess Medical Center, and Department of Medicine, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, Michigan
- Address reprints and correspondence: Dr Xiaoke Liu, Director, Device and EP Clinic, Borgess Medical Center, 1722 Shaffer St, Kalamazoo, MI 49048Device and EP Clinic, Borgess Medical Center, 1722 Shaffer St, Kalamazoo, MI 49048
| | | | - G. Glenn Kabell
- Division of Cardiology, Borgess Medical Center, and Department of Medicine, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, Michigan
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Mizukami K, Yokoshiki H, Mitsuyama H, Watanabe M, Tenma T, Matsui Y, Tsutsui H. Predictors of high defibrillation threshold in patients with implantable cardioverter-defibillator using a transvenous dual-coil lead. Circ J 2014; 79:77-84. [PMID: 25391259 DOI: 10.1253/circj.cj-14-0860] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Defibrillation testing (DT) is considered a standard procedure during implantable cardioverter-defibrillator (ICD) implantation. However, little is known about the factors that are significantly related to patients with high defibrillation threshold (DFT) using the present triad system. METHODS AND RESULTS We examined 286 consecutive patients who underwent ICD implantation with a transvenous dual-coil lead and DT from December 2000 to December 2011. We defined patients who required 25 J or more by the implanted device as the high DFT group, and those who required less than 25 J as the normal DFT group. For each patient, assessment parameters included underlying disease, comorbidities, NYHA functional class, drugs, and echocardiographic measures. The high DFT group consisted of 12 patients (4.2%). Multivariate analysis identified 3 independent predictors for high DFT: atrial fibrillation (odds ratio (OR) 4.85, 95% confidence interval (CI) 1.24-22.33, P=0.023), hypertension (OR 4.01, 95% CI 1.08-15.96, P=0.039), thickness of interventricular septum (IVS) >12 mm (OR 4.82, 95% CI 1.17-20.31, P=0.030). CONCLUSIONS Atrial fibrillation, hypertension and IVS hypertrophy were significantly associated with high DFT. Identification of such patients could help to lower the risk of complications with DT.
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Affiliation(s)
- Kazuya Mizukami
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
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Hsu JC, Marcus GM, Al-Khatib SM, Wang Y, Curtis JP, Sood N, Parker MW, Kluger J, Lampert R, Russo AM. Predictors of an inadequate defibrillation safety margin at ICD implantation: insights from the National Cardiovascular Data Registry. J Am Coll Cardiol 2014; 64:256-64. [PMID: 25034061 DOI: 10.1016/j.jacc.2014.01.085] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/22/2014] [Accepted: 01/27/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Defibrillation testing is often performed to establish effective arrhythmia termination, but predictors and consequences of an inadequate defibrillation safety margin (DSM) remain largely unknown. OBJECTIVES The aims of this study were to develop a simple risk score predictive of an inadequate DSM at implantable cardioverter-defibrillator (ICD) implantation and to examine the association of an inadequate DSM with adverse events. METHODS A total of 132,477 ICD Registry implantations between 2010 and 2012 were analyzed. Using logistic regression models, factors most predictive of an inadequate DSM (defined as the lowest successful energy tested <10 J from maximal device output) were identified, and the association of an inadequate DSM with adverse events was evaluated. RESULTS Inadequate DSMs occurred in 12,397 patients (9.4%). A simple risk score composed of 8 easily identifiable variables characterized patients at high and low risk for an inadequate DSM, including (with assigned points) age <70 years (1 point); male sex (1 point); race: black (4 points), Hispanic (2 points), or other (1 point); New York Heart Association functional class III (1 point) or IV (3 points); no ischemic heart disease (2 points); renal dialysis (3 points); secondary prevention indication (1 point); and ICD type: single-chamber (2 points) or biventricular (1 point) device. An inadequate DSM was associated with greater odds of complications (odds ratio: 1.22; 95% confidence interval: 1.09 to 1.37; p = 0.0006), hospital stay >3 days (odds ratio: 1.24; 95% confidence interval: 1.19 to 1.30; p < 0.0001), and in-hospital mortality (odds ratio: 1.96; 95% confidence interval: 1.63 to 2.36; p < 0.0001). CONCLUSIONS A simple risk score identified ICD recipients at risk for an inadequate DSM. An inadequate DSM was associated with an increased risk for in-hospital adverse events.
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Affiliation(s)
- Jonathan C Hsu
- Cardiac Electrophysiology Section, Division of Cardiology, University of California, San Diego, San Diego, California.
| | - Gregory M Marcus
- Section of Cardiac Electrophysiology, Division of Cardiology, University of California, San Francisco, San Francisco, California
| | - Sana M Al-Khatib
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
| | - Yongfei Wang
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Jeptha P Curtis
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Nitesh Sood
- Cardiac Arrhythmia Services, Southcoast Health System, Fall River, Massachusetts
| | - Matthew W Parker
- Division of Cardiology, Hartford Hospital, Hartford, Connecticut
| | - Jeffrey Kluger
- Division of Cardiology, Hartford Hospital, Hartford, Connecticut
| | - Rachel Lampert
- Section of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Andrea M Russo
- Cooper Medical School of Rowan University, Cooper University Hospital, Camden, New Jersey
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Affiliation(s)
- Andrea M. Russo
- From the Cooper Medical School of Rowan University, Camden, NJ (A.M.R.); and Cleveland Clinic Foundation, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, OH (M.K.C.)
| | - Mina K. Chung
- From the Cooper Medical School of Rowan University, Camden, NJ (A.M.R.); and Cleveland Clinic Foundation, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, OH (M.K.C.)
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PATEL MEHULB, PANDYA KHYATI, THAKUR RANJANK. Assessment of Adequate Safety Margin Using Single Coupling Interval-Upper Limit of Vulnerability Test. Pacing Clin Electrophysiol 2014; 37:95-103. [DOI: 10.1111/pace.12251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 07/05/2013] [Accepted: 07/09/2013] [Indexed: 11/28/2022]
Affiliation(s)
- MEHUL B. PATEL
- Sparrow Thoracic and Cardiovascular Institute, Division of Cardiology; Michigan State University; Lansing Michigan
| | - KHYATI PANDYA
- Sparrow Thoracic and Cardiovascular Institute, Division of Cardiology; Michigan State University; Lansing Michigan
| | - RANJAN K. THAKUR
- Sparrow Thoracic and Cardiovascular Institute, Division of Cardiology; Michigan State University; Lansing Michigan
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Smits K, Virag N, Swerdlow CD. Impact of defibrillation testing on predicted ICD shock efficacy: Implications for clinical practice. Heart Rhythm 2013; 10:709-17. [DOI: 10.1016/j.hrthm.2013.01.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Indexed: 12/25/2022]
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Jain SKA, Ghanbari H, Hourani R, Larsen TR, Daccarett M, Machado C. Echocardiographic parameters to predict inadequate defibrillation safety margin in patients receiving implantable cardioverter defibrillators for primary prevention. J Interv Card Electrophysiol 2013; 37:79-85. [DOI: 10.1007/s10840-012-9764-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 11/20/2012] [Indexed: 10/27/2022]
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VISCHER ANNINAS, STICHERLING CHRISTIAN, KÜHNE MICHAELS, OSSWALD STEFAN, SCHAER BEATA. Role of Defibrillation Threshold Testing in the Contemporary Defibrillator Patient Population. J Cardiovasc Electrophysiol 2012; 24:437-41. [DOI: 10.1111/jce.12042] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nakai T, Ohkubo K, Okumura Y, Kunimoto S, Kasamaki Y, Watanabe I, Hirayama A. Risk of defibrillation threshold testing in severe heart failure patient: A case of cardiac resynchronization therapy (CRT-D) with acute myocardial infarction. J Arrhythm 2012. [DOI: 10.1016/j.joa.2012.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Cheng Z, Turakhia M, Lo R, Gupta A, Zei PC, Hsia HH, Al-ahmad A, Wang PJ. Incidence and clinical predictors of low defibrillation safety margin at time of implantable defibrillator implantation. J Interv Card Electrophysiol 2012; 34:93-100. [DOI: 10.1007/s10840-011-9648-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 11/15/2011] [Indexed: 11/27/2022]
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SMITS KAREL, VIRAG NATHALIE. Impact of Defibrillation Test Protocol and Test Repetition on the Probability of Meeting Implant Criteria. Pacing and Clinical Electrophysiology 2011; 34:1515-26. [DOI: 10.1111/j.1540-8159.2011.03166.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Michowitz Y, Lellouche N, Contractor T, Bourke T, Wiener I, Buch E, Boyle N, Bersohn M, Shivkumar K. Defibrillation threshold testing fails to show clinical benefit during long-term follow-up of patients undergoing cardiac resynchronization therapy defibrillator implantation. Europace 2011; 13:683-8. [PMID: 21252192 DOI: 10.1093/europace/euq519] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The utility of defibrillation threshold testing in patients undergoing implantable cardioverter-defibrillator (ICD) implantation is controversial. Higher defibrillation thresholds have been noted in patients undergoing implantation of cardiac resynchronization therapy defibrillators (CRT-D). Since the risks and potential benefits of testing may be higher in this population, we sought to assess the impact of defibrillation safety margin or vulnerability safety margin testing in CRT-D recipients. METHODS AND RESULTS A total of 256 consecutive subjects who underwent CRT-D implantation between January 2003 and December 2007 were retrospectively reviewed. Subjects were divided into two groups based on whether (n= 204) or not (n= 52) safety margin testing was performed. Patient characteristics, tachyarrhythmia therapies, procedural results, and clinical outcomes were recorded. Baseline characteristics, including heart failure (HF) severity, were comparable between the groups. Four cases of HF exacerbation (2%), including one leading to one death, were recorded in the tested group immediately post-implantation. No complications were observed in the untested group. After a mean follow-up of 32 ± 20 months, the proportion of appropriate shocks in the two groups was similar (31 vs. 25%, P = 0.49). There were three cases of failed appropriate shocks in the tested group, despite adequate safety margins at implantation, whereas no failed shocks were noted in the untested group. Survival was similar in the two groups. CONCLUSION Defibrillation efficacy testing during implant of CRT-D was associated with increased morbidity and did not predict the success of future device therapy or improve survival during long-term follow-up.
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Affiliation(s)
- Yoav Michowitz
- UCLA Cardiac Arrhythmia Center, Ronald Reagan UCLA Medical Center, Los Angeles, CA 90095, USA.
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Sato A, Chinushi M, Iijima K, Watanabe H, Izumi D, Furushima H, Sonoda K, Hasegawa K, Yagihara N, Aizawa Y. An appropriate defibrillation threshold obtained by the combined connection between two shock leads and ICD generator. Intern Med 2011; 50:2815-8. [PMID: 22082895 DOI: 10.2169/internalmedicine.50.5792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 60-year-old man with arrhythmogenic right ventricular cardiomyopathy was readmitted for the battery exchange of his implantable cardioverter-defibrillator (ICD). Since (i) he had been treated with a dual-coil shock lead (Sprint Fidelis, Medtronic) and (ii) pre-operative venography showed mild collateral flow to the left subclavian vein, a single-coil lead was additionally implanted. However, the single-coil defibrillation system was unable to terminate the induced ventricular fibrillation (VF), thus dual defibrillation shock pathways were created using the connection to the superior vena cava coil of the Fidelis lead. The combined connections of the two shock leads provided an appropriate margin of the defibrillation threshold.
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Affiliation(s)
- Akinori Sato
- Division of Cardiology, Niigata University Graduate School of Medical and Dental Sciences, Japan
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Smits K, Virag N. Estimating the Parameter Distributions of Defibrillation Shock Efficacy Curves in a Large Population. Ann Biomed Eng 2010; 38:1314-25. [DOI: 10.1007/s10439-009-9890-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 12/24/2009] [Indexed: 10/20/2022]
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KOLB CHRISTOF, TZEIS STYLIANOS, ZRENNER BERNHARD. Defibrillation Threshold Testing: Tradition or Necessity? Pacing and Clinical Electrophysiology 2009; 32:570-2; discussion 572. [DOI: 10.1111/j.1540-8159.2009.02328.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Stockburger M. [Single- and dual-chamber ICDs: Are there still significant differences compared to pacemakers with regard to implantation and follow-up?]. Herzschrittmacherther Elektrophysiol 2008; 19 Suppl 1:6-13. [PMID: 19169730 DOI: 10.1007/s00399-008-0610-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Due to bulky generator size, abdominal pocket preparation and epicardial defibrillator lead placement, cardioverter-defibrillator (ICD) implantation was initially an extensive surgical intervention, which had to be performed in the operating room by cardiac surgeons under general anesthesia. The development of transvenously applicable endocardial defibrillator leads rendered thoracotomy unnecessary. The decrease in generator size enabled pectoral implantation. As a consequence of the simplified surgical procedure, implantation by cardiologists or electrophysiologists in the catheterization laboratory under local anesthesia and brief deep sedation with preserved spontaneous respiration was made possible. As a result, the implantation techniques of ICDs and pacemakers are converging. The present article illustrates the still existing significant differences between ICD and pacemaker treatment with regard to implantation and follow-up.
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Rosenheck S, Sharon Z, Weiss A. Long-Term Follow-Up of Patients with Relatively High Effective Defibrillation Threshold during Cardioverter Defibrillator Implantation with Endocardial Leads. Cardiology 2009; 112:107-13. [DOI: 10.1159/000141463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 04/10/2008] [Indexed: 11/19/2022]
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COOPER JONASA, LATACHA MATTHEWP, SOTO GABRIELE, GARMANY RICHARDG, GLEVA MARYEJ, CHEN JANE, FADDIS MITCHELLN, SMITH TIMOTHYW. The Azygos Defibrillator Lead for Elevated Defibrillation Thresholds: Implant Technique, Lead Stability, and Patient Series. Pacing and Clinical Electrophysiology 2008; 31:1405-10. [DOI: 10.1111/j.1540-8159.2008.01203.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Blatt JA, Poole JE, Johnson GW, Callans DJ, Raitt MH, Reddy RK, Marchlinski FE, Yee R, Guarnieri T, Talajic M, Wilber DJ, Anderson J, Chung K, Wong WS, Mark DB, Lee KL, Bardy GH. No benefit from defibrillation threshold testing in the SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial). J Am Coll Cardiol 2008; 52:551-6. [PMID: 18687249 DOI: 10.1016/j.jacc.2008.04.051] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 03/19/2008] [Accepted: 04/03/2008] [Indexed: 11/19/2022]
Abstract
OBJECTIVES This study investigated whether defibrillation threshold (DFT) testing during implantable cardioverter-defibrillator (ICD) implantation predicts clinical outcomes. BACKGROUND Defibrillation testing is often performed during insertion of ICDs to confirm shock efficacy. There are no prospective data to suggest that this procedure improves outcomes when modern ICDs are implanted for primary prevention of sudden death. METHODS The analysis included the 811 patients who were randomized to the ICD arm of the SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) and had the device implanted. The DFT testing protocol in SCD-HeFT was designed to limit shock testing in a primary prevention heart failure population. RESULTS Baseline DFT data were available for 717 patients (88.4%). All 717 patients had a DFT of < or =30 J, the maximum output of the device in this study. The DFT was < or =20 J in 97.8% of patients. There was no survival difference between patients with a lower DFT (< or =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. CONCLUSIONS Low baseline DFTs were obtained in patients with stable, optimally treated heart failure during ICD implantation for primary prevention of sudden death. First shock efficacy for ventricular tachyarrhythmias was high regardless of baseline DFT testing results. Baseline DFT testing did not predict long-term mortality or shock efficacy in this study.
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Affiliation(s)
- Joseph A Blatt
- Department of Cardiology, University of Washington, Box 356422, 1959 NE Pacific Street, Seattle, Washington 98195, USA.
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GULA LORNEJ, MASSEL DAVID, KRAHN ANDREWD, YEE RAYMOND, SKANES ALLANC, KLEIN GEORGEJ. Is Defibrillation Testing Still Necessary? A Decision Analysis and Markov Model. J Cardiovasc Electrophysiol 2008; 19:400-5. [DOI: 10.1111/j.1540-8167.2007.01095.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The results of intraoperative and postoperative predischarge implantable cardioverter-defibrillator (ICD) testing of 211 consecutive patients, starting at 15 J and requiring two successful terminations of induced VT/VF with a relative defibrillation safety margin (DSM) of >10 J, were reviewed. The aim was to define the type of intraoperative response that would make postoperative predischarge testing unnecessary. The intraoperative responses were divided into three types: A, a DSM > or =10 J and an absolute energy level of < or =20 J; B, a DSM of > or =10 J and an absolute energy level of >20 J; and C, a DSM <10 J and an absolute energy level of >20 J. At operation, the responses to defibrillation were A, 88.6%; B, 7.1%; and C, 4.3%. Accepting an A response only would leave 11.4% of the patients for postoperative testing. The positive and negative predictive values for diagnosing a postoperative C response were 0.78 and 0.97, respectively. Similarly, the predictive values for diagnosing a postoperative B or C response were 0.71 and 0.97, respectively. The postoperative testing responses were A, 89.1%; B, 4.3%; and C, 6.6%. In summary, an intraoperative A response was sufficient to make a postoperative defibrillation testing unnecessary, while it was found that intraoperative B and C responders should undergo postoperative testing. Applying these criteria, approximately 90% of the patients could be discharged without any postoperative induction test.
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Affiliation(s)
- Bengt Sandstedt
- Division of Cardiology, Sahlgrenska University Hospital, S-413 45 Göteborg, Sweden
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Abstract
Ventricular fibrillation (VF) has been induced at implantable cardioverter defibrillator (ICD) implant to ensure reliable sensing, detection, and defibrillation. Despite its risks, the value was self-evident for early ICDs: failure of defibrillation was common, recipients had a high risk of ventricular tachycardia (VT) or VF, and the only therapy for rapid VT or VF was a shock. Today, failure of defibrillation is rare, the risk of VT/VF is lower in some recipients, antitachycardia pacing is applied for fast VT, and vulnerability testing permits assessment of defibrillation efficacy without inducing VF in most patients. This review reappraises ICD implant testing. At implant, defibrillation success is influenced by both predictable and unpredictable factors, including those related to the patient, ICD system, drugs, and complications. For left pectoral implants of high-output ICDs, the probability of passing a 10 J safety margin is approximately 95%, the probability that a maximum output shock will defibrillate is approximately 99%, and the incidence of system revision based on testing is < or = 5%. Bayes' Theorem predicts that implant testing identifies < or = 50% of patients at high risk for unsuccessful defibrillation. Most patients who fail implant criteria have false negative tests and may undergo unnecessary revision of their ICD systems. The first-shock success rate for spontaneous VT/VF ranges from 83% to 93%, lower than that for induced VF. Thus, shocks for spontaneous VT/VF fail for reasons that are not evaluated at implant. Whether system revision based on implant testing improves this success rate is unknown. The risks of implant testing include those related to VF and those related to shocks alone. The former may be due to circulatory arrest alone or the combination of circulatory arrest and shocks. Vulnerability testing reduces risks related to VF, but not those related to shocks. Mortality from implant testing probably is 0.1-0.2%. Overall, VF should be induced to assess sensing in approximately 5% of ICD recipients. Defibrillation or vulnerability testing is indicated in 20-40% of recipients who can be identified as having a higher-than-usual probability of an inadequate defibrillation safety margin based on patient-specific factors. However, implant testing is too risky in approximately 5% of recipients and may not be worth the risks in 10-30%. In 25-50% of ICD recipients, testing cannot be identified as either critical or contraindicated.
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Affiliation(s)
- Charles D Swerdlow
- Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, and the David Geffen School of Medicine, UCLA, Los Angeles, California, USA.
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Mainigi SK, Cooper JM, Verdino RJ. To the Editor - Response. Heart Rhythm 2007; 4:253-254. [DOI: 10.1016/j.hrthm.2006.11.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Leong-Sit P, Gula LJ, Diamantouros P, Krahn AD, Skanes AC, Yee R, Klein GJ. Effect of defibrillation testing on management during implantable cardioverter-defibrillator implantation. Am Heart J 2006; 152:1104-8. [PMID: 17161062 DOI: 10.1016/j.ahj.2006.06.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Accepted: 06/07/2006] [Indexed: 11/27/2022]
Abstract
BACKGROUND Verification of defibrillation efficacy by defibrillation threshold (DFT) testing during implantable cardioverter-defibrillator implantation is the current standard. Generally, defibrillation of ventricular fibrillation at 10 J below the maximum output of a device is felt to establish an adequate safety margin. Nonetheless, DFT testing adds to cost and carries some potential for morbidity, whereas its impact on outcomes in the modern era of defibrillator technology is unclear. We aimed to determine the frequency that DFT testing resulted in a change at device implant and to identify clinical and echocardiographic predictors of the need for DFT testing. METHODS We reviewed all implantable cardioverter-defibrillators that were implanted at the London Health Sciences Centre (Ontario, Canada) from June 1999 to August 2003 and used multivariate analysis to determine variables associated with DFT test failures and elevated DFT values. When a defibrillation failure was not observed, a lowest energy to defibrillate (LED) was recorded. RESULTS Among 168 implants, DFT testing was successful with a minimum 10-J safety margin in 152 (90%), whereas the remaining 16 required changes at device implant. In a multivariate analysis, use of amiodarone was independently associated with DFT failure (odds ratio, 4.6; 95% confidence interval, 1.2-17.0). Significantly higher mean DFT/LED values were observed among patients on amiodarone (1.36 J; P = .0041). Those with nonischemic cardiomyopathy had a higher mean DFT/LED compared with those with ischemic cardiomyopathy (1.44 J; P = .028). CONCLUSIONS Use of amiodarone is associated with a 4-fold increase in risk of DFT failure and subsequent need for changes at implant to achieve a safe threshold. Defibrillation threshold testing appears to be most useful for patients taking amiodarone.
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Affiliation(s)
- Peter Leong-Sit
- Division of Cardiology, University of Western Ontario, London, Ontario, Canada
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Affiliation(s)
- Sumeet K Mainigi
- Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, 19104, USA
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Mainigi SK, Cooper JM, Russo AM, Nayak HM, Lin D, Dixit S, Gerstenfeld EP, Hsia HH, Callans DJ, Marchlinski FE, Verdino RJ. Elevated defibrillation thresholds in patients undergoing biventricular defibrillator implantation: Incidence and predictors. Heart Rhythm 2006; 3:1010-6. [PMID: 16945792 DOI: 10.1016/j.hrthm.2006.05.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 05/30/2006] [Indexed: 02/07/2023]
Abstract
BACKGROUND The biventricular implantable cardioverter-defibrillator (ICD) is an important therapy for select patients with severe heart failure. Given reported risk factors for elevated defibrillation thresholds (DFTs), patients undergoing biventricular ICD placement would be suspected of having a higher incidence of elevated DFT. OBJECTIVES The purpose of this study was to examine the clinical predictors and mortality risk of elevated DFTs in patients receiving a biventricular ICD. METHODS Characteristics of patients undergoing biventricular ICD placement with an elevated DFT were compared to those without an elevated DFT. RESULTS An elevated DFT was found in 14 (12%) of 121 patients. Mean QRS duration was 210 +/- 50 ms in the elevated DFT group and 171 +/- 36 ms in the normal DFT group (P = .01). Patients with a QRS duration >or=200 ms were more likely to have an elevated DFT than those with a duration <200 ms (odds ratio 13.4, 95% confidence interval 3.1-66.7, P <.01). No other clinical characteristics were associated with an elevated DFT. More than 90% of patients with an elevated DFT achieved an adequate safety margin through system modification or manipulation of their drug regimen. An elevated DFT did not have an impact on 2-year mortality. CONCLUSION Patients with a biventricular ICD had a 12% incidence of elevated DFT in our sequential patient cohort. QRS duration prior to biventricular ICD placement is the most powerful predictor of patients at risk for an elevated DFT. An elevated DFT does not have an impact on mortality, perhaps because of successful implementation of system modifications to ensure an adequate defibrillation safety margin.
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Affiliation(s)
- Sumeet K Mainigi
- Department of Medicine, Electrophysiology Section, Division of Cardiovascular Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
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Abstract
INTRODUCTION Defibrillation testing of the implantable cardioverter-defibrillator (ICD) is considered a standard and required practice at the time of implantation. How much testing, if any in some cases, should be performed, however, remains unknown. METHODS AND RESULTS Included in this retrospective analysis were 835 patients (77% men; age 65 +/- 13 years) who received transvenous ICDs between January 1996 and December 2003. One hundred twenty-nine (15.5%) had intraoperative defibrillation threshold (DFT) testing, 503 (60.2%) had limited defibrillation safety margin testing, and 203 (24.3%) had no defibrillation testing. We compared the outcome (success of ICD therapies against spontaneous VT/VF events and survival) of the three groups of patients, who in some respects had important clinical differences. The success of the first delivered shocks against VT/VF was similar for DFT (91%), safety margin testing (91%), and no-testing (92%) groups; and the second shocks terminated the remaining episodes in all three groups. Sudden-death-free survival rates were similar in the three groups, however, the overall long-term survival rate was significantly lower in the no-testing group (58%) than in the DFT (74%) and safety margin testing (69%) groups (P < 0.0005). Multivariate analysis found no strong predictors of sudden death, but there were several independent predictors of overall mortality including lack of ICD testing (HR: 2.031, CI: 1.253-3.290, P = 0.004). CONCLUSION In this select patient cohort, success of ICD therapies and sudden-death-free survival were similar in patients who had DFT, safety margin testing, and no testing, but overall survival was significantly lower in the no-testing group. Thus in the absence of prospective mortality data, a minimum of safety margin ICD testing should remain standard practice.
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Affiliation(s)
- Luis A Pires
- Heart Rhythm Center and the Division of Cardiology, Department of Medicine, St. John Hospital and Medical Center, Detroit, Michigan 48236, USA.
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Russo AM, Sauer W, Gerstenfeld EP, Hsia HH, Lin D, Cooper JM, Dixit S, Verdino RJ, Nayak HM, Callans DJ, Patel V, Marchlinski FE. Defibrillation threshold testing: is it really necessary at the time of implantable cardioverter-defibrillator insertion? Heart Rhythm 2005; 2:456-61. [PMID: 15840466 DOI: 10.1016/j.hrthm.2005.01.015] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2004] [Accepted: 01/04/2005] [Indexed: 12/25/2022]
Abstract
OBJECTIVES The purpose of this study was to (1) determine how often implantable cardioverter-defibrillator (ICD) system modifications were needed to obtain an adequate safety margin for defibrillation, (2) identify how often and for what indications defibrillation threshold (DFT) testing was not performed, and (3) identify factors predicting the need for modification. BACKGROUND Ventricular fibrillation (VF) typically is induced at the time of ICD insertion. Although DFT testing often is minimized, a safety margin of 10 J has been utilized as a standard of care. However, current devices offer technology such as biphasic waveforms and high outputs, and the need for testing has been questioned. METHODS We reviewed the records of the last 1,139 patients undergoing initial ICD placement, generator replacement, or revision. RESULTS Seventy-one patients (6.2%) were identified as having an unacceptably high DFT (<10 J safety margin) requiring intervention, and some required >1 modification. Use of a high-output device alone was not enough to obtain an adequate DFT in 48% (34/71) of patients who required modifications (3% of the total population). No arrhythmia inductions were performed in 54 patients (4.7%) because of well-defined clinical conditions. Patients who required system modification had a lower ejection fraction, were younger, were less likely to have coronary artery disease, were more likely to be undergoing upgrade/generator replacement, and were more likely to be taking amiodarone. Long-term mortality was not different between the group of patients who required modification compared with those who did not (17% vs 20%, P = NS). CONCLUSIONS Routine VF induction and documentation of effective defibrillation still remains a reasonable part of ICD placement because an inadequate safety margin may occur in >6% of patients. The incidence of patients who were inappropriate for testing based on well-defined clinical conditions is small (<5%) in this unselected large series. Although some clinical features may predict the need for system modification, additional studies are needed to better define "acceptable efficacy" of ICDs in preventing sudden death prior to altering these standards in selected patients.
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Affiliation(s)
- Andrea M Russo
- University of Pennsylvania Health System, Philadelphia, Pennsylvania 19104, USA.
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Higgins S, Mann D, Calkins H, Estes NAM, Strickberger SA, Breiter D, Lang D, Hahn S. One conversion of ventricular fibrillation is adequate for implantable cardioverter-defibrillator implant: An analysis from the Low Energy Safety Study (LESS). Heart Rhythm 2005; 2:117-22. [PMID: 15851281 DOI: 10.1016/j.hrthm.2004.10.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2004] [Accepted: 10/26/2004] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The purpose of this study was to analyze defibrillation conversion data from the Low Energy Safety Study (LESS) to determine how implant criteria that use fewer inductions of ventricular fibrillation (VF) correlate with outcome and, in particular, to assess the reliability of using a single VF induction and test shock at 14 J. BACKGROUND A safety margin of 10 J has become standard for implantation of an implantable cardioverter-defibrillator (ICD), but the specifics and rigor of the implant test sequence are not standardized. METHODS In LESS, 611 ICD recipients completed a rigorous VF induction test scheme that began at 14 J and continued until the energy that succeeded three times without a failure was determined (DFT++). The data were analyzed to determine how well the outcome of the first 14-J shock and various other combinations of first and/or second shocks predicted a rigorous gold standard of DFT++ < or =21 J (i.e., three successes at < or =21 J). RESULTS The positive predictive accuracy for the 91% of patients in whom the first 14-J shock succeeded was virtually identical to the positive predictive accuracy for the commonly used criteria of two successes at < or =17 J (99.1% vs 99.0%, P = .69), and slightly higher than the positive predictive accuracy for two successes at < or =21 J (98.8%, P = .51). A single success at 17 J or 21 J had a somewhat lower positive predictive accuracy of 98.2% (P = .17). Eliminating VF induction testing would have resulted in a significantly lower positive predictive accuracy of 97.1% (P = .01). CONCLUSIONS A single conversion success at 14 J on the first VF induction provides similar positive predictive accuracy as two successes at 17 J or 21 J. Using this criterion, 91% of patients meet implant criteria with a single induction of ventricular fibrillation.
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Affiliation(s)
- Steven Higgins
- Scripps Memorial Hospital, La Jolla, California. 92037, USA.
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Abstract
The assessment of defibrillation (DFT) efficacy has long been the standard of care during defibrillator implantation. To ensure an acceptable DFT safety margin, early defibrillator systems frequently required that the shock polarity and the location, type, or number of electrodes had to be altered. Advances in defibrillator and lead technology have resulted in lower and more consistent DFT thresholds in the range of 10 J, with an infrequent requirement to modify the DFT system. Yet, one can make an argument for and against continuation of DFT testing at the time of defibrillator implantation. The goal of this paper is to address both the data that do support and the data that do not support continuation of DFT testing at the time of device implantation. Scientifically, DFT testing should be abandoned only when prospective evidence demonstrates that defibrillator implantation without testing is as safe and has the same mortality benefits as implantation with testing. The most attractive aspect of eliminating DFT efficacy testing is that more patients may have the opportunity to be treated with this life-saving therapy. Perhaps there are alternative strategies to improve accessibility to defibrillator therapy without possibly eroding its effectiveness. In the end, will lives be saved or lost if we discontinue DFT efficacy testing and lower the barriers to implantable defibrillator therapy?
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Carlsson J, Schulte B, Erdogan A, Sperzel J, Güttler N, Schwarz T, Pitschner HF, Neuzner J. Prospective randomized comparison of two defibrillation safety margins in unipolar, active pectoral defibrillator therapy. Pacing Clin Electrophysiol 2003; 26:613-8. [PMID: 12710322 DOI: 10.1046/j.1460-9592.2003.00102.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Various techniques are used to establish defibrillation efficacy and to evaluate defibrillation safety margins in patients with an ICD. In daily practice a safety margin of 10 J is generally accepted. However, this is based on old clinical data and there are no data on safety margins using current ICD technology with unipolar, active pectoral defibrillators. Therefore, a randomized study was performed to test if the likelihood of successful defibrillation at defibrillation energy requirement (DER) + 5 J and + 10 J is equivalent. Ninety-six patients (86 men; age 61.0 +/- 10.3 years; ejection fraction 0.341 +/- 0.132; coronary artery disease [n = 65], dilated cardiomyopathy [n = 18], other [n = 13]) underwent implantation of an active pectoral ICD system with unidirectional current pathway and a truncated, fixed tilt biphasic shock waveform. The defibrillation energy requirement (DER) was determined with the use of a step-down protocol (delivered energy 15, 10, 8, 6, 4, 3, 2 J). The patients were then randomized to three inductions of ventricular fibrillation at implantation and three at predischarge testing with shock strengths programmed to DER + 5 J at implantation and + 10 J at predischarge testing or vice versa. The mean DER in the total study population was 7.88 +/- 2.96 J. The number of defibrillation attempts was 288 for + 5 J and 288 for + 10 J. The rate of successful defibrillation was 94.1% (DER + 5 J) and 98.9% (DER + 10 J; P < 0.01 for equivalence). Charge times for DER + 5 J were significantly shorter than for DER + 10 J (3.65 +/- 1.14 vs 5.45 +/- 1.47 s; P < 0.001). A defibrillation safety margin of DER + 5 J is associated with a defibrillation probability equal to the standard DER + 10 J. In patients in whom short charge times are critical for avoidance of syncope, a safety margin of DER + 5 J seems clinically safe for programming of the first shock energy.
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Affiliation(s)
- Joerg Carlsson
- Department of Cardiology, Kerckhoff-Clinic, Bad Nauheim, Germany.
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Gold MR, Breiter D, Leman R, Rashba EJ, Shorofsky SR, Hahn SJ. Safety of a single successful conversion of ventricular fibrillation before the implantation of cardioverter defibrillators. Pacing Clin Electrophysiol 2003; 26:483-6. [PMID: 12687873 DOI: 10.1046/j.1460-9592.2003.00077.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
UNLABELLED Multiple successful conversions of ventricular fibrillation (VF) at 10 J below the maximum output of implantable cardioverter defibrillator (ICD) have been recommended as a minimum device implantation criterion. This recommendation is based on the probabilistic properties of defibrillation that necessitates multiple shocks to establish an adequate safety margin for the conversion of subsequent spontaneous arrhythmias. We hypothesized that a single successful shock at a 14 J may suffice. METHODS AND RESULTS The Low Energy Safety Study (LESS) enrolled 720 patients undergoing initial ICD implantation with a dual-coil transvenous lead and active pulse generator. At implant, an enhanced defibrillation threshold (DFT++) was determined by a rigorous protocol beginning at 14 J, and requiring at least 4 shocks. Fifty percent of all patients were then randomized to full output shock energy and the conversion rates for spontaneous ventricular tachyarrhythmias at rates > 200 beats/min were measured. There were 318 patients randomized to 31 J, of whom 254 were successfully defibrillated by an initial 14 J shock. During a mean follow-up of 24 +/- 12 months, 112 spontaneous VF episodes occurred in 31 patients. The combined conversion success of the first and second shock (when needed) did not differ between the subgroup of patients who were successfully defibrillated by an initial 14 J shock, regardless of the results of additional testing, and the whole cohort who underwent more systematic testing (97% vs 97%). All spontaneous episodes of VF were successfully treated during long-term follow-up. CONCLUSIONS A first successful shock of 14 J may be a sufficient endpoint to allow the implantation of ICDs with the Triad lead configuration, when programming all shocks to 31 J.
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Affiliation(s)
- Michael R Gold
- MUSC, Division of Cardiology, 96 Jonathan Lucas Street, PO Box 250623, Charleston, SC 29425.
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Gold MR, Higgins S, Klein R, Gilliam FR, Kopelman H, Hessen S, Payne J, Strickberger SA, Breiter D, Hahn S. Efficacy and temporal stability of reduced safety margins for ventricular defibrillation: primary results from the Low Energy Safety Study (LESS). Circulation 2002; 105:2043-8. [PMID: 11980683 DOI: 10.1161/01.cir.0000015508.59749.f5] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Traditionally, a safety margin of at least 10 J between the maximum output of the pulse generator and the energy needed for ventricular defibrillation has been used because lower safety margins were associated with unacceptably high rates of failed defibrillation and sudden cardiac death. The Low Energy Safety Study (LESS) was a prospective, randomized assessment of the safety margin requirements for modern implantable cardioverter-defibrillator (ICD) systems. METHODS AND RESULTS A total of 636 patients undergoing initial ICD implantation with a dual-coil lead and active pulse generator were evaluated. The defibrillation threshold (DFT) and enhanced DFT (DFT+ and DFT++) were measured using a modified step-down protocol. Conversion testing of induced ventricular fibrillation before discharge, at 3 months, and at 12 months was performed, as was randomization to chronic programming at either 2 steps above DFT++ or maximal output. The induced ventricular fibrillation data had conversion success rates of 91.4%, 97.9%, 99.1%, 99.6%, and 99.8% for safety margins of 0, 1, 2, 3, and 4 steps above the DFT++, respectively. A margin of 4 to 6 J was adequate to maintain high conversion success over time (98.9% before discharge versus 99.2% at 12 months; P=NS). Over a mean follow-up of 24+/-13 months, conversion of spontaneously occurring ventricular tachyarrhythmias >200 bpm was identical (97.3%), despite a safety margin difference of 5.2+/-1.1 J for the 2-step group versus 20.8+/-4.2 J for maximal output. CONCLUSIONS With a rigorous implantation algorithm, a safety margin of about 5 J is adequate for safe implantation of modern ICD systems.
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Affiliation(s)
- Michael R Gold
- Medical University of South Carolina, Division of Cardiology, Charleston 29425, USA.
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Wolbrette DL, Naccarelli GV. Management of implantable cardioverter defibrillator patients: role of predischarge electrophysiologic testing and proper patient instruction before hospital discharge. Curr Opin Cardiol 2001; 16:72-5. [PMID: 11124722 DOI: 10.1097/00001573-200101000-00011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Routine postoperative testing of implanted defibrillators is still debated. While a high-risk subgroup of patients can be identified where this testing is mandatory, those with good results at implants may be less likely to benefit from further testing. Recent data suggests routine testing is justified due to a low, but potentially life-threatening, device failure rate found during postoperative testing. Additionally, patient education is important in the predischarge period. Patients must be knowledgeable regarding potential environmental electromagnetic interference with normal function of their device. Adequate discharge instructions will help reduce patient anxiety over returning to their normal daily activities, and help them adjust psychologically to their defibrillator.
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Affiliation(s)
- D L Wolbrette
- Section of Cardiology, The Penn State University, The Milton S. Hershey Medical Center, 500 University Drive, Hershey, Pennsylvania, USA
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Boriani G, Biffi M, Frabetti L, Maraschi M, Branzi A. High defibrillation threshold at cardioverter defibrillator implantation under amiodarone treatment: favorable effects of D, L-sotalol. Heart Lung 2000; 29:412-6. [PMID: 11080321 DOI: 10.1067/mhl.2000.109388] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A 57-year-old man with primary dilated cardiomyopathy and obesity received an implantable cardioverter defibrillator because of recurrent, poorly tolerated ventricular tachycardia despite continuous treatment with amiodarone. When the device was implanted, assessment of the ability to defibrillate induced ventricular fibrillation showed high energy requirements, with a lack of conventional safety margin between energies effective at defibrillation testing and maximal device output. Treatment with oral amiodarone was withdrawn and substituted with oral sotalol. A repeat defibrillation test, performed 54 days after amiodarone withdrawal and during D,L -sotalol treatment, showed a reduction in defibrillation energy requirements. In view of this experience, replacement of amiodarone treatment with an alternate class III agent (D,L -sotalol or other agents, if available) can be considered as a possible option in case of high defibrillation threshold at the time of the implantation in a patient receiving continuous amiodarone treatment.
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Affiliation(s)
- G Boriani
- Institute of Cardiology, University of Bologna, Bologna, Italy
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Neuzner J, Liebrich A, Jung J, Himmrich E, Pitschner HF, Winter J, Vester EG, Michel U, Nisam S, Heisel A. Safety and efficacy of implantable defibrillator therapy with programmed shock energy at twice the augmented step-down defibrillation threshold: results of the prospective, randomized, multicenter Low-Energy Endotak Trial. Am J Cardiol 1999; 83:34D-39D. [PMID: 10089837 DOI: 10.1016/s0002-9149(99)00037-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Whether the safety and efficacy of implantable cardioverter defibrillator (ICD) therapy can be assured with lower output devices is an important question. The purpose of this study was to evaluate whether programming the device output at twice the augmented defibrillation threshold was as safe and effective as using the maximum energy. Patients indicated for ICD therapy, but without slow monomorphic ventricular tachycardia (MVT), who achieved an augmented defibrillation threshold (DFT plus) < or = 15 joules (J) with a single endocardial lead system and a biphasic defibrillator were included in the study. Prior to ICD implantation, patients were randomized into 2 groups. The shock energies in test group patient were set as follows: first shock at twice DFT plus, the second to fifth shocks at maximum output (34 J). In control group patients, all shocks were programmed at 34 J. The study population consisted of 166 consecutive patients (mean age 57.4 +/- 12.1 years, mean left ventricular ejection fraction 36.8 +/- 13.8%). Mean DFT plus was 9.6 +/- 3.2 J in test group patients and 10.1 +/- 3.5 J in control group patients (p = 0.36). During a mean follow-up of 24.2 +/- 9.6 months, 736 arrhythmia episodes were analyzed. The first shock efficacy was 98.3% in the test group patients versus 97.4% in the control group (p = 0.45). Total mortality was 6%, equally distributed in both study groups. The results of this study prove that the method of doubling the defibrillation energy at the DFT plus level provides an adequate safety margin in defibrillator therapy.
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Affiliation(s)
- J Neuzner
- Kerckhoff Clinic, Bad Nauheim, Germany
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Pires LA, Lehmann MH, Steinman RT, Baga JJ, Schuger CD. Sudden death in implantable cardioverter-defibrillator recipients: clinical context, arrhythmic events and device responses. J Am Coll Cardiol 1999; 33:24-32. [PMID: 9935004 DOI: 10.1016/s0735-1097(98)00519-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES We sought to investigate the nature of terminal events and potential contributory clinical and nonclinical (e.g., device-related) factors associated with sudden death (SD) in recipients of an implantable cardioverter-defibrillator (ICD). BACKGROUND The ICD is very effective in terminating ventricular tachycardia (VT) or ventricular fibrillation (VF), but protection against SD is not absolute. Little is known about the nature and potential causes of SD in patients with ICDs. METHODS We analyzed 25 cases of out-of-hospital SD among patients enrolled in the clinical investigation of the Cadence Tiered-Therapy Defibrillator System. RESULTS All patients (24 men and 1 woman, mean age 62+/-10 years) received epicardial lead systems. The majority (92%) had coronary artery disease and a previous myocardial infarction (MI), with a mean left ventricular ejection fraction 0.25+/-0.07. At device implantation, the mean defibrillation threshold was 13+/-5 J. Sudden death occurred 13+/-11 months later. Twenty patients (80%) had received appropriate ICD therapies before death, and 18 (72%) were receiving > or = 1 antiarrhythmic drugs at the time of death. Sudden death was tachyarrhythmia-associated in 16 patients (64%), non-tachyarrhythmia-associated in 7 (28%) and indeterminate in 2 (8%). In the 16 patients with tachyarrhythmia-associated SD, the overall first therapy success rate in tachycardia and fibrillation zones was 60% and 67%, respectively. However, despite protracted therapies (> or = 2 shocks) in 7 (66%) of 12 patients who received fibrillation therapies, the final tachyarrhythmic episode was ultimately terminated by the ICD in 15 (94%) of the 16 patients, whereas 1 patient died after multiple (initially successful) internal and external shocks for intractable VT/VF during exercise. In 10 patients (40%) one or more, primarily clinical, factors potentially contributory to SD were identified: heart failure (n=8), angina (n=2), hypokalemia (n=1), adverse antiarrhythmic drug treatment (n=1) and acute MI (n=1). An additional 10 patients (40%) had experienced an increase in frequency of ICD shocks within 3 months of SD. Appropriate battery voltages and normal circuitry function were found in all devices interrogated and analyzed after death. CONCLUSIONS In this select group of patients receiving a third-generation ICD, SD was associated with VT or VF events in nearly two-thirds of patients, and death occurred despite ultimately successful, although often protracted, device therapies. These observations, along with evidence of recent worsening clinical status, suggest acute cardiac mechanical dysfunction as a frequent terminal factor. In recipients with ICDs, SD directly attributable to device failure seems to be rare.
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Affiliation(s)
- L A Pires
- Arrhythmia Center/Sinai Hospital and Wayne State University School of Medicine, Detroit, Michigan, USA
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Schauerte P, Diem B, Ziegert K, Franke A, Hanrath P, Stellbrink C. Influence of body position on defibrillation thresholds of nonthoracotomy implantable defibrillators: a prospective randomized evaluation. J Cardiovasc Electrophysiol 1998; 9:696-702. [PMID: 9684717 DOI: 10.1111/j.1540-8167.1998.tb00956.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Defibrillation thresholds (DFTs) usually are determined with the patient in the supine position. However, patients may be in the upright position when a shock is delivered during follow-up, which may explain some first shock failures observed clinically. This study investigated whether body posture affects defibrillation energy requirements of nonthoracotomy implantable cardioverter defibrillators with biphasic shocks. METHODS AND RESULTS Using a step up-down protocol, DFTs were compared intraindividually in 52 patients ("active-can" sytems in 41 patients, two-lead systems in 11 patients) for the supine and upright positions as achieved by a tilt table. The mean DFT was 7.3 +/- 4.2 J in the supine versus 9.2 +/- 4.8 J in the upright position (P = 0.002). Repeated comparison in reversed order 3 months after implantation in 22 patients revealed thresholds of 6.2 +/- 2.5 J (supine) versus 8.4 +/- 3.7 J (upright; P < 0.03) 1 week and 4.4 +/- 2.4 J (supine) versus 6.2 +/- 4.1 J (upright; P < 0.04) 3 months after implantation. DFTs decreased significantly for both body positions from 1 week to 3 months after implantation (P < 0.04). CONCLUSION (1) DFTs for biphasic shocks delivered by nonthoracotomy defibrillators are higher in the upright compared to the supine body position. (2) Differences remain significant 3 months after implantation. For both body positions, DFT decreases significantly from 1 week to 3 months after implantation. These findings have important implications for programming first shock energy to lower than maximal values or for development of devices with lower maximal stored energy.
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Affiliation(s)
- P Schauerte
- Department of Cardiology, University Hospital RWTH Aachen, Germany
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Abstract
The necessity of routine invasive implantable cardioverter-defibrillator (ICD) testing before hospital discharge was analyzed in 268 patients. In 98% of the patients, invasive ICD testing was not necessary if a preimplant electrophysiologic test was performed; most of the observed problems can be solved by noninvasive control.
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Affiliation(s)
- A Wieckhorst
- Department of Cardiology, University of Goettingen, Göttingen, Germany
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Abstract
Complete postoperative evaluation of implantable cardioverter-defibrillators (ICDs) before discharge, including arrhythmia induction, has been the standard since their introduction. Whereas the original ICDs provided little telemetered information and used separate pace-sense and defibrillation leads, modern, third-generation devices provide pace-sense function information in addition to other data and are used in conjunction with integrated transvenous endocardial leads that combine pace-sense and defibrillation function. Changes in lead position, which can potentially result in either an inability to detect fibrillation or to terminate it, should be mirrored by changes in resting pace-sense function. Thus, for newer ICDs implanted with integrated endocardial lead systems, it is possible that in at least some cases predischarge arrhythmia inductions can be avoided. Two hundred patients receiving third-generation ICDs in conjunction with integrated transvenous leads were evaluated before discharge. Defibrillation detection or termination problems were seen in 8. Declines in resting R-wave amplitude and pacing impedance were significantly associated with such complications (-7 +/- 5 vs -0.3 +/- 2.3 mV [p <0.0001] and -158 +/- 138 vs -93 +/- 76 omega [p <0.05], for those with vs without complications, respectively), as were gross right ventricular lead migrations on chest x-ray. No patient with a defibrillation complication had an R-wave change of <3 mV. However, 13% of patients without complications had R-wave changes of >3 mV. It is concluded that a pace-sense evaluation of ICDs may be a satisfactory screen to determine those who need to go on to complete testing with arrhythmia induction in selected cases.
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Affiliation(s)
- D N Weiss
- Florida Arrhythmia Consultants, Fort Lauderdale, USA
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