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A prospective, randomized comparison in humans of defibrillation efficacy of a standard transvenous ICD system with a totally subcutaneous ICD system (The S-ICD® system)
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Heart Rhythm, Vol 2, No 9, September 2005
Jeffrey Goldberger, MD, Joseph Levine, MD, Kelley P. Anderson, MD. Northwestern University, Chicago, IL, University of North Carolina, Chapel Hill, NC, St. Francis Hospital, Roslyn, NY, Marshfield Clinic, Marshfield, WI. Objective: The purpose of the present study was to determine whether the time from diagnosis of cardiomyopathy to randomization affects prognosis and the degree of ICD benefit that patients receive using a post-hoc analysis of DEFINITE data. The DEFINITE trial randomized 458 patients with non-ischemic dilated cardiomyopathy, a left ventricular ejection fraction of less than 36 percent and an arrhythmia marker to receive standard medical therapy with or witout an ICD. Patients were randomized regardless of the duration of known cardiomyopathy as long as a reversible cause of left ventricular dysfunction was not present. Patients were divided into recently and remotely diagnosed non-ischemic cardiomyopathy groups based on the time from diagnosis of cardiomyopathy to randomization. To categorize patients, cut-points of 3 and 9 months were used. Results: Patients with recently diagnosed cardiomyopathy who received an ICD had better survival than those treated with standard therapy at both cut-points. This difference in survival was significant at 3 months (P ⬍ 0.05) and was borderline at 9 months (P ⫽ 0.058) (Figures 1 and 2). Adjusting for baseline characteristics that were different between the groups did not substantially alter these findings.
Figure 1
Figure 2 Conclusion: ICD therapy appears to benefit patients with recently diagnosed cardiomyopathy. Thus, ICD therapy should be considered in such patients as soon as they are identified. Disclosure: A. Kadish, Bard Electrophysiology Investigator; Guidant Corporation Investigator; Medtronic, Inc. Investigator; St. Jude Medical, US Sales Division Investigator; St. Jude Medical, US Sales Division Scientific Study/Trial; A. Schaechter, St. Jude Medical, US Sales Division Scientific Study/Trial; H. Subacius, St. Jude Medical, US Sales Division Scientific Study/Trial; E. Thattassery, None; W.E. Sanders, St. Jude Medical, US Sales Division Investigator; A. Dyer, None; J. Goldberger, Guidant Corporation Investigator; Medtronic, Inc. Investigator; St. Jude Medical, US Sales Division Investigator; J. Levine, St. Jude Medical, US Sales Division Investigator; K.P. Anderson, None.
AB-6107 A PROSPECTIVE, RANDOMIZED COMPARISON IN HUMANS OF DEFIBRILLATION EFFICACY OF A STANDARD TRANSVENOUS ICD SYSTEM WITH A TOTALLY SUBCUTANEOUS ICD SYSTEM (THE S-ICD® SYSTEM) Andrew A. Grace, MD, Warren M. Smith, MD, Margaret A Hood, MD, Derek T. Connelly, MD, Francis D. Murgatroyd, MD, Ian G. Crozier, MD, Iain C. Melton, MD, David J. Wright, MD, Riccardo Cappato, MD, and Gust H. Bardy, MD. University of Cambridge, Cambridge, United Kingdom, Auckland City Hospital, Auckland, New Zealand, The Cardiothoracic Centre, Liverpool, United Kingdom, Christchurch Hospital, Christchurch, New Zealand, Christchurch Hospital, Christchuch, New Zealand, Istituto Policlinico San Donato, San Donato Milanese, Italy, Seattle Institute for Cardiac Research, Seattle, WA. Background: An ICD that does not require transvenous (TV) leads may alter adult and pediatric ICD practice patterns by eliminating lead complications and procedural barriers. However, it remains unproved whether defibrillation is possible for the subcutaneous-only ICD (S-ICD) at technically feasible energy levels and how those levels compare to TV-ICDs. Objective: To compare, in a prospective multicenter randomized trial, defibrillation thresholds (DFTs) for an S-ICD to that of a standard TV-ICD at surgery. Methods: In 41 patients (pts) with standard ICD indications, the DFT was measured using a step-down, skip-up technique after 10 seconds of induced VF. The protocol was completed in 37 pts. TV DFTs were tested at an initial energy of 20 J. For the S-ICD system, an electrically active canister electrode, positioned in the anterolateral axillary line in the sixth intercostal space, was paired with a parasternal electrode 3 cm left of the sternal midline. The defibrillation coil was centered at the fifth intercostal space. No fluoroscopy was used for S-ICD insertion. The starting S-ICD energy was 40 J. A custom generator (Cameron Health, Inc.) was used to conduct S-ICD DFT testing. Lead repositioning was allowed for the TV system but prohibited for the S-ICD. Results: The TV-ICD DFTs were 12 ⫽ 9 J. The matching S-ICD DFTs were 39 ⫽ 19 J (P ⬍ .001). No pt complications were observed with either system. However, repositioning of the TV-ICD was required in 6/37 pts. On the other hand, the S-ICD was inserted in as few as 6 minutes, excluding incision suturing with no repositioning. Conclusion: As anticipated, the S-ICD defibrillates at higher energy levels than a TV-ICD. However, energy levels are much lower than typical external transthoracic requirements (⬎100 J). In addition, S-ICD energies are within the range of what is technically feasible for a device specifically geared for easy subcutaneous-only insertion. The S-ICD does not require fluoroscopy, has potential for very short insertion times, and did not require lead repositioning (like the TV-ICD). The S-ICD may well serve as a viable alternative to TV-ICDs in many pts. Disclosure: A.A. Grace, Cameron Health Consultant/Advisor; W.M. Smith, Cameron Health Consultant/Advisor; M.A. Hood, None; D.T. Connelly, Cameron Health Consultant/Advisor; F.D. Murgatroyd, None; I.G. Crozier, None; I.C. Melton, None; D.J. Wright, None; R. Cappato, Cameron Health Consultant/Advisor; G.H. Bardy, Cameron Health Board Member/Officer/Trustee, Consultant/Advisor; Guidant Consultant/Advisor, Speakers Bureau; Medtronic Investigator, Speakers Bureau, Scientific Study/Trial. YI1-1 NEUREGULIN BUT NOT ENDOTHELIN SIGNALING IS REQUIRED FOR ATRIOVENTRICULAR CONDUCTION TISSUE DEVELOPMENT David J. Milan, MD, Andrea C. Giokas, BS, Randall T. Peterson, PhD, Calum A. MacRaeMD, PhD. Massachusetts General Hospital, Charlestown, MA. Background: Molecular characterization of atrioventricular (AV) conduction system development has been limited by difficulty in assessing early
Heart Rhythm, Vol 2, No 9, September 2005
Jeffrey Goldberger, MD, Joseph Levine, MD, Kelley P. Anderson, MD. Northwestern University, Chicago, IL, University of North Carolina, Chapel Hill, NC, St. Francis Hospital, Roslyn, NY, Marshfield Clinic, Marshfield, WI. Objective: The purpose of the present study was to determine whether the time from diagnosis of cardiomyopathy to randomization affects prognosis and the degree of ICD benefit that patients receive using a post-hoc analysis of DEFINITE data. The DEFINITE trial randomized 458 patients with non-ischemic dilated cardiomyopathy, a left ventricular ejection fraction of less than 36 percent and an arrhythmia marker to receive standard medical therapy with or witout an ICD. Patients were randomized regardless of the duration of known cardiomyopathy as long as a reversible cause of left ventricular dysfunction was not present. Patients were divided into recently and remotely diagnosed non-ischemic cardiomyopathy groups based on the time from diagnosis of cardiomyopathy to randomization. To categorize patients, cut-points of 3 and 9 months were used. Results: Patients with recently diagnosed cardiomyopathy who received an ICD had better survival than those treated with standard therapy at both cut-points. This difference in survival was significant at 3 months (P ⬍ 0.05) and was borderline at 9 months (P ⫽ 0.058) (Figures 1 and 2). Adjusting for baseline characteristics that were different between the groups did not substantially alter these findings.
Figure 1
Figure 2 Conclusion: ICD therapy appears to benefit patients with recently diagnosed cardiomyopathy. Thus, ICD therapy should be considered in such patients as soon as they are identified. Disclosure: A. Kadish, Bard Electrophysiology Investigator; Guidant Corporation Investigator; Medtronic, Inc. Investigator; St. Jude Medical, US Sales Division Investigator; St. Jude Medical, US Sales Division Scientific Study/Trial; A. Schaechter, St. Jude Medical, US Sales Division Scientific Study/Trial; H. Subacius, St. Jude Medical, US Sales Division Scientific Study/Trial; E. Thattassery, None; W.E. Sanders, St. Jude Medical, US Sales Division Investigator; A. Dyer, None; J. Goldberger, Guidant Corporation Investigator; Medtronic, Inc. Investigator; St. Jude Medical, US Sales Division Investigator; J. Levine, St. Jude Medical, US Sales Division Investigator; K.P. Anderson, None.
AB-6107 A PROSPECTIVE, RANDOMIZED COMPARISON IN HUMANS OF DEFIBRILLATION EFFICACY OF A STANDARD TRANSVENOUS ICD SYSTEM WITH A TOTALLY SUBCUTANEOUS ICD SYSTEM (THE S-ICD® SYSTEM) Andrew A. Grace, MD, Warren M. Smith, MD, Margaret A Hood, MD, Derek T. Connelly, MD, Francis D. Murgatroyd, MD, Ian G. Crozier, MD, Iain C. Melton, MD, David J. Wright, MD, Riccardo Cappato, MD, and Gust H. Bardy, MD. University of Cambridge, Cambridge, United Kingdom, Auckland City Hospital, Auckland, New Zealand, The Cardiothoracic Centre, Liverpool, United Kingdom, Christchurch Hospital, Christchurch, New Zealand, Christchurch Hospital, Christchuch, New Zealand, Istituto Policlinico San Donato, San Donato Milanese, Italy, Seattle Institute for Cardiac Research, Seattle, WA. Background: An ICD that does not require transvenous (TV) leads may alter adult and pediatric ICD practice patterns by eliminating lead complications and procedural barriers. However, it remains unproved whether defibrillation is possible for the subcutaneous-only ICD (S-ICD) at technically feasible energy levels and how those levels compare to TV-ICDs. Objective: To compare, in a prospective multicenter randomized trial, defibrillation thresholds (DFTs) for an S-ICD to that of a standard TV-ICD at surgery. Methods: In 41 patients (pts) with standard ICD indications, the DFT was measured using a step-down, skip-up technique after 10 seconds of induced VF. The protocol was completed in 37 pts. TV DFTs were tested at an initial energy of 20 J. For the S-ICD system, an electrically active canister electrode, positioned in the anterolateral axillary line in the sixth intercostal space, was paired with a parasternal electrode 3 cm left of the sternal midline. The defibrillation coil was centered at the fifth intercostal space. No fluoroscopy was used for S-ICD insertion. The starting S-ICD energy was 40 J. A custom generator (Cameron Health, Inc.) was used to conduct S-ICD DFT testing. Lead repositioning was allowed for the TV system but prohibited for the S-ICD. Results: The TV-ICD DFTs were 12 ⫽ 9 J. The matching S-ICD DFTs were 39 ⫽ 19 J (P ⬍ .001). No pt complications were observed with either system. However, repositioning of the TV-ICD was required in 6/37 pts. On the other hand, the S-ICD was inserted in as few as 6 minutes, excluding incision suturing with no repositioning. Conclusion: As anticipated, the S-ICD defibrillates at higher energy levels than a TV-ICD. However, energy levels are much lower than typical external transthoracic requirements (⬎100 J). In addition, S-ICD energies are within the range of what is technically feasible for a device specifically geared for easy subcutaneous-only insertion. The S-ICD does not require fluoroscopy, has potential for very short insertion times, and did not require lead repositioning (like the TV-ICD). The S-ICD may well serve as a viable alternative to TV-ICDs in many pts. Disclosure: A.A. Grace, Cameron Health Consultant/Advisor; W.M. Smith, Cameron Health Consultant/Advisor; M.A. Hood, None; D.T. Connelly, Cameron Health Consultant/Advisor; F.D. Murgatroyd, None; I.G. Crozier, None; I.C. Melton, None; D.J. Wright, None; R. Cappato, Cameron Health Consultant/Advisor; G.H. Bardy, Cameron Health Board Member/Officer/Trustee, Consultant/Advisor; Guidant Consultant/Advisor, Speakers Bureau; Medtronic Investigator, Speakers Bureau, Scientific Study/Trial. YI1-1 NEUREGULIN BUT NOT ENDOTHELIN SIGNALING IS REQUIRED FOR ATRIOVENTRICULAR CONDUCTION TISSUE DEVELOPMENT David J. Milan, MD, Andrea C. Giokas, BS, Randall T. Peterson, PhD, Calum A. MacRaeMD, PhD. Massachusetts General Hospital, Charlestown, MA. Background: Molecular characterization of atrioventricular (AV) conduction system development has been limited by difficulty in assessing early