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Vanneman MW. Anesthetic Considerations for Percutaneous Coronary Intervention for Chronic Total Occlusions-A Narrative Review. J Cardiothorac Vasc Anesth 2021; 36:2132-2142. [PMID: 34493436 DOI: 10.1053/j.jvca.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 07/18/2021] [Accepted: 08/01/2021] [Indexed: 11/11/2022]
Abstract
Advancing stent technology has enabled interventional cardiologists to perform percutaneous coronary intervention (PCI) to open chronic total occlusions (CTOs). Because PCI for CTOs improve patient anginal symptoms and quality of life, these procedures have been increasing over the past decade. Compared to standard PCI, these procedures are technically more difficult, with prolonged procedure time and increased risk of complications. Accordingly, anesthesiologists are increasingly being asked to provide sedation for these patients in the cardiac catheterization suite. In CTO PCI, anesthesiologists are more likely to encounter complications such as coronary artery perforation, malignant arrhythmias, non-target vessel ischemia, bleeding and shock. Additionally, CTO PCI may be supported by mechanical circulatory support devices. Understanding the procedural techniques of these complex PCI procedures is important to enable optimal anesthetic care in these patients. This narrative review discusses the pathophysiology, risks, benefits, procedural steps, and main anesthetic considerations for patients undergoing CTO PCI. Despite a growing body of literature, future research is still required to elucidate optimal anesthetic and mechanical support strategies in patients undergoing CTO PCI.
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Affiliation(s)
- Matthew W Vanneman
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA.
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Sanchez DJ, Lozano IF. Implantable cardioverter-defibrillator in hypertrophic cardiomyopathy. Glob Cardiol Sci Pract 2018; 2018:31. [PMID: 30393643 PMCID: PMC6209444 DOI: 10.21542/gcsp.2018.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Sudden cardiac death (SCD) is the most devastating complication in hypertrophic cardiomyopathy (HCM). The implantable cardioverter–defibrillator (ICD) has proven to be effective in SCD prevention in several clinical scenarios. In HCM population, it has demonstrated to successfully abort life-threatening ventricular arrhythmias despite the extreme morphology characteristic of HCM, often with massive degrees of left ventricular hypertrophy and/or LV outflow tract obstruction. Studies showed a high rate of appropriate intervention in secondary prevention and in primary prevention of patients considered at high risk. This appropriate intervention rate is even more significant considering the young and otherwise healthy patients that compose HCM population. Since SCD incidence in HCM is relatively low, optimal identification of patients at high risk is crucial. Classical strategy of risk stratification based on clinical risk factors has several limitations and has proven to overestimate risk. A new risk prediction model that provides individual 5-year estimated risk appears to be superior to traditional models based on bivariate risk factors. Perioperative complications seem to be similar to those related to the implant of other cardiac devices, while long-term complications have been traditionally in the spotlight. HCM patients are considered more vulnerable to ICD-related complications and inappropriate ICD therapy because of their young age at implant and increased prevalence of atrial fibrillation, but long-term follow-up data on ICD-related complications in general practice is limited. The subcutaneous implantable cardioverter defibrillator seems to be a safe and effective alternative in HCM, although long-term data are scarce.
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Quinn TA, Kohl P. Rabbit models of cardiac mechano-electric and mechano-mechanical coupling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 121:110-22. [PMID: 27208698 PMCID: PMC5067302 DOI: 10.1016/j.pbiomolbio.2016.05.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/01/2016] [Indexed: 12/11/2022]
Abstract
Cardiac auto-regulation involves integrated regulatory loops linking electrics and mechanics in the heart. Whereas mechanical activity is usually seen as 'the endpoint' of cardiac auto-regulation, it is important to appreciate that the heart would not function without feed-back from the mechanical environment to cardiac electrical (mechano-electric coupling, MEC) and mechanical (mechano-mechanical coupling, MMC) activity. MEC and MMC contribute to beat-by-beat adaption of cardiac output to physiological demand, and they are involved in various pathological settings, potentially aggravating cardiac dysfunction. Experimental and computational studies using rabbit as a model species have been integral to the development of our current understanding of MEC and MMC. In this paper we review this work, focusing on physiological and pathological implications for cardiac function.
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Affiliation(s)
- T Alexander Quinn
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Canada.
| | - Peter Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, Faculty of Medicine, University of Freiburg, Freiburg, Germany; National Heart and Lung Institute, Imperial College London, London, UK
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SHIH MICHAELJ, KAKODKAR SIDDHARTHA, KAID YOUSEF, HASSEL JONATHANL, YARLAGADDA SANTI, FOGG LOUISF, MADIAS CHRISTOPHER, KRISHNAN KOUSIK, TROHMAN RICHARDG. Reassessing Risk Factors for High Defibrillation Threshold: The EF-SAGA Risk Score and Implications for Device Testing. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2016; 39:483-9. [DOI: 10.1111/pace.12838] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 01/27/2016] [Accepted: 02/21/2016] [Indexed: 11/27/2022]
Affiliation(s)
- MICHAEL J. SHIH
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - SIDDHARTH A. KAKODKAR
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - YOUSEF KAID
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - JONATHAN L. HASSEL
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - SANTI YARLAGADDA
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - LOUIS F. FOGG
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - CHRISTOPHER MADIAS
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - KOUSIK KRISHNAN
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
| | - RICHARD G. TROHMAN
- Department of Medicine, Division of Cardiology, Electrophysiology, Arrhythmia and Pacemaker Service; Rush University Medical Center; Chicago Illinois
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Ohlow MA, Roos M, Lauer B, Geller JC. Incidence of ineffective safety margin testing (<10 J) and efficacy of routine subcutaneous array insertion during implantable cardioverter defibrillator implantation. Indian Pacing Electrophysiol J 2016; 16:47-52. [PMID: 27676160 PMCID: PMC5832618 DOI: 10.1016/j.ipej.2016.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/19/2016] [Indexed: 11/30/2022] Open
Abstract
The purpose of this study was to assess (1) the incidence of safety margin testing <10 J (SMT) and (2) the efficacy/safety of routinely adding a subcutaneous array (SQA) (Medtronic 6996SQ) for these patients. Patients with SMT smaller than a 10-J safety margin from maximum output were considered to have very high readings and underwent SQA insertion. These patients were compared with the rest of the patients who had acceptable SMT (≥10 J). A total of 616 patients underwent ICD implantation during the analysis period. Of those, 16 (2.6%) had SMT <10 J. By univariate analysis, younger age, and non-ischemic cardiomyopathy, were all significant predictors of SMT <10 J (p < 0.05). In all 16 cases, other methods to improve SMT prior to array insertion were attempted but failed for all patients: reversing shock polarity (n = 15), removing the superior vena cava coil (n = 14), reprogramming shock waveform (n = 9), and repositioning right ventricular lead (n = 9). Addition of the SQA successfully increased SMT to within safety margin for all patients (32 ± 2 versus 21 ± 3 J; p < 0.001). Follow-up (mean 48.1 ± 21 months) was available for all patients with SQA, only 2 cases with inappropriate shocks due to atrial fibrillation had to be noted. None of the patients experienced complications due to SQA implantation. SMT <10 J occur in about 2.6% of patients undergoing ICD implantation. SQA insertion corrects this problem without procedural/mid-term complications.
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Affiliation(s)
- Marc-Alexander Ohlow
- Department of Cardiology, Zentralklinik, Robert-Koch-Allee 9, 99437 Bad Berka, Germany.
| | - Marcus Roos
- Clinic for Electrophysiology, Heart Center, Salzburger Leite 1, 67616 Bad Neustadt, Germany
| | - Bernward Lauer
- Department of Cardiology, Zentralklinik, Robert-Koch-Allee 9, 99437 Bad Berka, Germany
| | - J Christoph Geller
- Department of Invasive Electrophysiology, Zentralklinik, Robert-Koch-Allee 9, 99437 Bad Berka, Germany
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Larsen JM, Hjortshøj SP, Nielsen JC, Johansen JB, Petersen HH, Haarbo J, Johansen MB, Margrethe Thøgersen A. Single-coil and dual-coil defibrillator leads and association with clinical outcomes in a complete Danish nationwide ICD cohort. Heart Rhythm 2016; 13:706-12. [DOI: 10.1016/j.hrthm.2015.11.034] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Indexed: 11/29/2022]
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Ito H, Kawamura M, Badhwar N, Vedantham V, Tseng ZH, Lee BK, Lee RJ, Marcus GM, Gerstenfeld EP, Scheinman MM. The Effect of Direct Current Stimulation versus T-Wave Shock on Defibrillation Threshold Testing. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 38:1173-80. [PMID: 26137999 DOI: 10.1111/pace.12684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/03/2015] [Accepted: 06/22/2015] [Indexed: 11/28/2022]
Abstract
INTRODUCTION There are several methods to induce ventricular fibrillation (VF) during defibrillation threshold (DFT) testing. Delivering a shock at a critical time during the T wave (T-shock) is the conventional approach, while delivering a constant direct current voltage (DC stim) from the implantable cardioverter defibrillator is an alternative method. Only a few reports compare VF induction methods. The purpose of this study was to evaluate the effects and safety of DC stim versus T-shock. METHODS We retrospectively investigated 414 consecutive patients undergoing DFT testing. We compared the two groups (DC stim and T-shock) with respect to clinical characteristics, electrocardiogram (ECG) changes, and complications. RESULTS Ventricular arrhythmia, including ventricular tachycardia (VT) and VF, was induced by DC stim in 93 patients or T-shock in 321 patients. No more than three attempts were performed during one procedure. There was no significant difference in the baseline ECG, induced tachycardia cycle length (TCL), or complications between the two groups. However, the induced TCL was significantly shorter than the clinical TCL regardless of induction method (P = 0.001). Five patients suffered major complications (i.e., electromechanical dissociation or incessant VT). A history of atrial fibrillation was significantly greater in patients with major complications than the others (80% vs 24%, P = 0.004), and was an independent predictor on multivariate analysis. CONCLUSIONS There is no significant difference in induced TCL or complications between the DC stim and T-shock. The induced TCL is significantly shorter than clinical TCL regardless of induction method.
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Affiliation(s)
- Hiroyuki Ito
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Mitsuharu Kawamura
- Division of Cardiology, Department of Medicine, Showa University, Tokyo, Japan
| | - Nitish Badhwar
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Vasanth Vedantham
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Zian H Tseng
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Byron K Lee
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Randall J Lee
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Gregory M Marcus
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Edward P Gerstenfeld
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
| | - Melvin M Scheinman
- Division of Cardiac Electrophysiology, University of California San Francisco, San Francisco, California
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How to Manage a High Defibrillation Threshold in ICD Patients: and Does it Really Matter? CURRENT TREATMENT OPTIONS IN CARDIOVASCULAR MEDICINE 2013; 15:497-505. [DOI: 10.1007/s11936-013-0244-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lin EF, Dalal D, Cheng A, Marine JE, Nazarian S, Sinha S, Spragg DD, Tandri H, Halperin H, Calkins H, Berger RD, Tomaselli GF, Henrikson CA. Predictors of high defibrillation threshold in the modern era. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2012; 36:231-7. [PMID: 23121046 DOI: 10.1111/pace.12039] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 08/13/2012] [Accepted: 09/18/2012] [Indexed: 01/04/2023]
Abstract
INTRODUCTION High defibrillation threshold (DFT) is a clinical problem in 1-8% of implantable cardioverter-defibrillator implants. Some clinicians and investigators question whether the benefits of routine DFT testing outweigh the risks. Identification of the predictors of elevated DFT may allow selective application of DFT testing. However, the clinical characteristics of patients with high DFT in the modern era have not been well-defined. METHODS All patients who underwent DFT testing in our institution during an 8-year period were reviewed for this retrospective study. High DFT was defined as less than a 10-J safety margin on initial testing. For each case, the two cases preceding and two cases following by the same implanter were selected as controls. RESULTS Of the 2,138 patients who underwent DFT testing, 48 (2.2%) met criteria for high DFT. Compared to 192 control patients, patients with high DFT were more likely to be younger (P = 0.004), have nonischemic cardiomyopathy (P = 0.036), have a longer QRS interval (P = 0.026), and have a left ventricular ejection fraction (LVEF) ≤ 0.25 (P = 0.013). On multivariate analysis, only younger age (P = 0.016) and LVEF ≤ 0.25 (P = 0.010) remained statistically significant predictors of elevated DFT. CONCLUSIONS High DFT was identified in 2.2% of ICD implants in our institution in recent years. Although younger age and depressed LVEF predicts this problem, elevated DFT occurred in patients of all ages and ejection fractions. Elimination of routine DFT testing appears to be premature given the prevalence and unpredictability of elevated DFT.
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Affiliation(s)
- Edward F Lin
- Johns Hopkins University, Baltimore, Maryland, USA
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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] [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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Gold MR, Hedayati A, Alaeddini J, Payne JP, Bailin S, Sturdivant JL, Pradhan S, Oza AL. Temporal stability of defibrillation thresholds with cardiac resynchronization therapy. Heart Rhythm 2011; 8:1008-13. [DOI: 10.1016/j.hrthm.2011.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 02/02/2011] [Indexed: 11/29/2022]
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Quin EM, Cuoco FA, Forcina MS, Coker JB, Yoe RH, Spencer WH, Fernandes VL, Nielsen CD, Sturdivant JL, Leman RB, Wharton JM, Gold MR. Defibrillation thresholds in hypertrophic cardiomyopathy. J Cardiovasc Electrophysiol 2010; 22:569-72. [PMID: 21091965 DOI: 10.1111/j.1540-8167.2010.01943.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Defibrillation threshold (DFT) testing is performed in part to ensure an adequate safety margin for the termination of spontaneous ventricular arrhythmias. Left ventricular mass is a predictor of high DFTs, so patients with hypertrophic cardiomyopathy (HCM) are often considered to be at risk for increased defibrillation energy requirements. However, there are little prospective data addressing this issue. OBJECTIVE To assess DFTs in patients with HCM and evaluate the clinical predictors of elevated DFTs. METHODS Eighty-nine consecutive patients with HCM and 600 control patients with ischemic or nonischemic cardiomyopathy underwent a uniform modified step-down DFT testing protocol. DFT was compared between the control and HCM populations. Predictors of elevated DFT were evaluated in the HCM group. RESULTS There was no difference in DFT between HCM and control groups (10.4 ± 5.8 J vs 11.2 ± 5.6 J, respectively). Among patients with HCM, clinical parameters such as left ventricular ejection fraction, interventricular septal thickness, left ventricular mass, and QRS duration were not predictive of an elevated DFT. Only 3 patients (3.4%) with HCM had a DFT >20 J. CONCLUSION Patients with HCM do not have elevated DFTs as compared to more typical populations undergoing implantable cardioverter-defibrillator implant; high-energy devices or complex lead systems are not needed routinely in this population.
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Affiliation(s)
- Ernest M Quin
- Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Reynolds CR, Nikolski V, Sturdivant JL, Leman RB, Cuoco FA, Wharton JM, Gold MR. Randomized comparison of defibrillation thresholds from the right ventricular apex and outflow tract. Heart Rhythm 2010; 7:1561-6. [DOI: 10.1016/j.hrthm.2010.06.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 06/09/2010] [Indexed: 11/28/2022]
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ROBERTS BRETTD, HOOD ROBERTE, SABA MAGDIM, DICKFELD TIMMM, SALIARIS ANASTASIOSP, SHOROFSKY STEPHENR. Defibrillation Threshold Testing in Patients with Hypertrophic Cardiomyopathy. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2010; 33:1342-6. [DOI: 10.1111/j.1540-8159.2010.02843.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Theuns DA, Gold MR. Defibrillation threshold testing at implantation: can we predict the patient with a high defibrillation threshold? Europace 2010; 12:309-10. [DOI: 10.1093/europace/euq003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Nagai T, Kurita T, Satomi K, Noda T, Okamura H, Shimizu W, Suyama K, Aihara N, Kobayashi J, Kamakura S. QRS prolongation is associated with high defibrillation thresholds during cardioverter-defibrillator implantations in patients with hypertrophic cardiomyopathy. Circ J 2009; 73:1028-32. [PMID: 19359812 DOI: 10.1253/circj.cj-08-0744] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Although high defibrillation threshold (DFT) is a major and unavoidable clinical problem after implantation of an implantable cardioverter defibrillator (ICD), little is known about the cause and management of a high DFT in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to assess the predictors of a high DFT in patients with HCM. METHODS AND RESULTS Twenty-three patients with non-dilated HCM who underwent ICD implantation were included. The DFT at the time of the device implantation was measured in all patients. The patients were divided into 2 groups, a high DFT group (DFT >or=15J, n=13) and a low DFT group (DFT <15J, n=10); and their baseline characteristics were compared. The QRS duration was longer in the high than in the low DFT group (128 +/-31 vs 103 +/-12 ms, respectively; P=0.02). QRS duration, left ventricular (LV) end-systolic diameter, and LV ejection fraction were significant predictors of DFT in univariate analysis. However, in multivariate analysis, the only factor significantly associated with DFT was QRS duration (P=0.002). CONCLUSIONS QRS duration is the most consistent predictor of a high DFT in HCM patients undergoing ICD implantation.
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Affiliation(s)
- Takayuki Nagai
- Division of Cardiology, Department of Internal Medicine, National Cardiovascular Center, Suita, Japan
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Michael KA, Veldtman GR, Paisey JR, Yue AM, Robinson S, Allen S, Sunni NS, Kiesewetter C, Salmon T, Roberts PR, Morgan JM. Cardiac defibrillation therapy for at risk patients with systemic right ventricular dysfunction secondary to atrial redirection surgery for dextro-transposition of the great arteries. ACTA ACUST UNITED AC 2007; 9:281-4. [PMID: 17383987 DOI: 10.1093/europace/eum001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIM To review techniques of implantable cardioverter-defibrillators (ICD) in patients after Mustard surgery for arterial transposition. METHODS AND RESULTS Retrospective analysis of all Mustard patients receiving ICDs at our institution. Five patients (median age 24 years, range 19-35, 3 male) with systemic right ventricular dysfunction (sRV) dysfunction and New York Heart Association (NYHA) II and III, received ICDs. Implantation was performed transvenously in three patients, epicardial patches and subcutaneous arrays at surgery in two patients. Two patients required lead extraction and baffle stent angioplasty before ICD implantation. Defibrillation vectors incorporating the anterior sRV mass [i.e., sub-pulmonary left ventricle (pLV) to generator can, and between epicardial defibrillator patches], consistently achieved a minimum 10 joule(J) safety margin during defibrillation threshold (DFT) testing. Subcutaneous arrays and endocardial vectors that included a superior vena cava (SVC) electrode were less effective. One patient developed pulmonary oedema post-procedure. At a median 20 months, all patients were alive and in NYHA class II. Follow-up over 24 months documented multiple non-sustained ventricular tachycardia (VT) in the group and one patient had recurrent VT with aborted device therapy. CONCLUSION Defibrillator implantation in Mustard patients is challenging. Sub-optimal defibrillation should be anticipated and can be overcome using vectors which integrate the RV mass and high-energy devices. A staged procedure involving pre-implant interventions or separate DFT tests, where indicated, may be better tolerated by patients.
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Affiliation(s)
- Kevin A Michael
- Department of Clinical Electrophysiology, Wessex Cardiothoracic Centre, Southampton, UK.
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Watanabe H, Chinushi M, Sugiura H, Washizuka T, Komura S, Hosaka Y, Furushima H, Watanabe H, Hayashi J, Aizawa Y. Unsuccessful Internal Defibrillation in Brugada Syndrome: Focus on Refractoriness and Ventricular Fibrillation Cycle Length. J Cardiovasc Electrophysiol 2005; 16:262-6. [PMID: 15817083 DOI: 10.1046/j.1540-8167.2005.40579.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
INTRODUCTION In patients with Brugada syndrome, implantable cardioverter defibrillator (ICD) is the only reliable treatment to prevent sudden death though, in some cases, internal defibrillation may be unsuccessful. The aim of this study was to examine the determinants of defibrillation failure, with a focus on electrophysiologic characteristics. METHODS The study included 51 patients treated with ICD: 22 with Brugada syndrome and 29 with structural heart disease (SHD). The prevalence of defibrillation energy requirement precluding the programming of a 10-J safety margin, the mean right ventricular effective refractory period (ERP), and mean induced ventricular fibrillation cycle length (VFCL) from the stored ICD electrograms, were compared between the two patient groups. RESULTS High defibrillation requirements were observed in 18% of patients with Brugada syndrome versus 0% of patients with SHD. However, the patients with SHD had larger heart size than those with Brugada syndrome. Mean VFCL and mean ERP were both significantly shorter in patients with Brugada syndrome than in patients with SHD, and ERP and VFCL were significantly correlated. CONCLUSION Patients with Brugada syndrome have a high prevalence of high defibrillation energy requirement, and short ventricular ERP and VFCL.
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Affiliation(s)
- Hiroshi Watanabe
- Niigata University Graduate School of Medical and Dental Science, Niigata, Japan.
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Rashba EJ, Shorofsky SR, Brown T, Peters RW, Gold MR. Clinical predictors of atrial defibrillation thresholds with a dual-coil, active pectoral lead system. Heart Rhythm 2005; 2:49-54. [PMID: 15851265 DOI: 10.1016/j.hrthm.2004.10.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 10/19/2004] [Indexed: 11/24/2022]
Abstract
OBJECTIVES The purpose of this study was to identify clinical predictors of atrial defibrillation thresholds (DFTs) with standard implantable cardioverter-defibrillator (ICD) leads. BACKGROUND Atrial defibrillation can be achieved with active pectoral, dual-coil transvenous ICD lead systems. If clinical predictors of atrial defibrillation efficacy with these lead systems were identified, they could be used to predict which patients may require more complex lead systems for atrial defibrillation, such as a coronary sinus electrode. METHODS This was a prospective study of 135 consecutive patients undergoing initial ICD implant for standard indications. The lead system evaluated was a transvenous defibrillation lead with coils in the superior vena cava (SVC) and right ventricular apex (RV), and a left pectoral pulse generator emulator (CAN). The shocking pathway was RV-->SVC+CAN. Atrial DFT was measured using a step-up protocol. Clinical and echocardiographic parameters were evaluated as predictors of atrial DFT and multiple linear regression was performed. RESULTS Mean atrial DFT was 4.6 +/- 3.8 J. Atrial DFT was < or =3 J in 70 patients (52%) and < or = 10 J in 97% of patients. The highest atrial DFT was 20 J (one patient). Left atrial size (r = 0.21, P = .01) and left ventricular end-diastolic diameter (r = 0.19, P = .02) were independent predictors of atrial DFT. However, these two predictors accounted for only 6% of the variability in atrial DFT. CONCLUSIONS Clinical parameters are of limited use in predicting atrial DFT with a dual-coil, active pectoral ICD lead system. Because the RV--> SVC + CAN shocking pathway provides reliable atrial and ventricular defibrillation, this configuration should be preferred for combined atrial and ventricular ICDs.
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Affiliation(s)
- Eric J Rashba
- Division of Cardiology, University of Maryland School of Medicine, Baltimore, 21201, USA.
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Shukla HH, Flaker GC, Jayam V, Roberts D. High defibrillation thresholds in transvenous biphasic implantable defibrillators: clinical predictors and prognostic implications. Pacing Clin Electrophysiol 2003; 26:44-8. [PMID: 12685138 DOI: 10.1046/j.1460-9592.2003.00148.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of this study was to identify clinical characteristics that distinguish patients with high DFTs and assess the prognostic implication. DFTs testing is a lengthy, potentially painful, and a hazardous process. Little information is available concerning the identification of patients with high DFT who undergo ICD surgery with transvenous leads and biphasic energy. This study analyzed 968 patients from two separate clinical studies who received a Medtronic cardioverter defibrillator from January 1995 through November 1999 and who had DFT testing measured by a binary search protocol. Compared to 865 patients with low defibrillation thresholds (< 18 J), the 103 patients with high thresholds (> or = 18 J) had a lower LVEF (34 +/- 16.7 vs 38.3 +/- 16.2%, P = 0.01), a worse NYHA functional class (23% Class I, 43% Class II, 29% Class III, 5% Class IV vs. 27% Class I, 55% Class II, 17% Class III, 1% Class IV, P < 0.0001), had bypass surgery less often (10.7 vs 27.5%, P < 0.0001), used amiodarone within the past 6 weeks (42.7 vs 27.2%, P = 0.002), and had a history of ventricular fibrillation more often (44.7 vs 33.1%, P = 0.02). Information concerning the number of shocks delivered was available in 345 (35%) patients; 23 were in the high DFT group and 322 were in the low DFT group. Twelve (52%) of the 23 patients in the high DFT arm received 3.6 +/- 2.7 shocks (median 2.5) and 106 (33%) of the 322 patients with low DFT received 4.9 +/- 9.5 shocks (median 2). After 6 months the mortality rate of patients with high thresholds was 11.7 vs 7.8% in patients with low thresholds (P = 0.118). Using a multivariate logistic regression model the significant predictors of death were older age, higher NYHA class, lower LVEF, amiodarone use, had a presenting arrhythmia of ventricular fibrillation and CHF but not initial high defibrillation thresholds. The study found that (1) 11% of patients have high DFTs, (2) clinical characteristics that identify high defibrillation thresholds are NYHA Class III, IV, low ejection fraction, no previous history of bypass surgery, prior amiodarone use preoperatively, and presenting with ventricular fibrillation, and (3) while high DFTs were associated with a more ill patient population, there was no difference in survival in a 6-month follow-up. Patients with a predicted low DFTs may be eligible for abbreviated ICD testing while high risk patients require formal testing.
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Affiliation(s)
- Himanshu H Shukla
- Division of Cardiology, University of Missouri, Columbia, One Hospital Dr., MC314-Div. of Cardiology, Columbia, MO 65212, USA.
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Kirk MM, Shorofsky SR, Gold MR. Comparison of the effects of active left and right pectoral pulse generators on defibrillation efficacy. Am J Cardiol 2001; 88:1308-11. [PMID: 11728363 DOI: 10.1016/s0002-9149(01)02096-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- M M Kirk
- Department of Medicine, Division of Cardiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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22
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Rashba EJ, Olsovsky MR, Shorofsky SR, Kirk MM, Peters RW, Gold MR. Temporal decline in defibrillation thresholds with an active pectoral lead system. J Am Coll Cardiol 2001; 38:1150-5. [PMID: 11583896 DOI: 10.1016/s0735-1097(01)01483-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The objective of this study was to characterize temporal changes in defibrillation thresholds (DFTs) after implantation with an active pectoral, dual-coil transvenous lead system. BACKGROUND Ventricular DFTs rise over time when monophasic waveforms are used with non-thoracotomy lead systems. This effect is attenuated when biphasic waveforms are used with transvenous lead systems; however, significant increases in DFT still occur in a minority of patients. The long-term stability of DFTs with contemporary active pectoral lead systems is unknown. METHODS This study was a prospective assessment of temporal changes in DFT using a uniform testing algorithm, shock polarity and dual-coil active pectoral lead system. Thresholds were measured at implantation, before discharge and at long-term follow-up (70 +/- 40 weeks) in 50 patients. RESULTS The DFTs were 9.2 +/- 5.4 J at implantation, 8.3 +/- 5.8 J before discharge and 6.9 +/- 3.6 J at long-term follow-up (p < 0.01 by analysis of variance; p < 0.05 for long-term follow-up vs. at implantation or before discharge). The effect was most marked in a prespecified subgroup with high implant DFTs (> or =15 J). No patient developed an inadequate safety margin (< 9 J) during follow-up. CONCLUSIONS The DFTs declined significantly after implantation with an active pectoral, dual-coil transvenous lead system, and no clinically significant increases in DFT were observed. Therefore, routine defibrillation testing may not be required during the first two years after implantation with this lead system, in the absence of a change in the cardiac substrate or treatment with antiarrhythmic drugs.
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Affiliation(s)
- E J Rashba
- Division of Cardiology, University of Maryland School of Medicine, Baltimore, Maryland 21201-1595, USA.
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23
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Costeas XF, Strembelas PG, Markou DX, Stefanadis CI, Toutouzas PK. Subpectoral cardioverter-defibrillator implantation using a lateral approach. J Interv Card Electrophysiol 2000; 4:611-9. [PMID: 11141208 DOI: 10.1023/a:1026569700036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
INTRODUCTION Third-generation cardioverter-defibrillators have revolutionized management of ventricular tachyarrhythmias. Implantation can be performed in the electro-physiology laboratory, with minimal morbidity. Generator size has shrunk to the point that subcutaneous implantation is feasible and safe, even under local anesthesia. The prepectoral technique, however, is associated with increased mechanical stress to the subcutaneous tissue and can predispose to device erosion or infection. These complications may be avoided by submuscular placement. Among subpectoral techniques, the lateral approach offers unrestricted ability to deploy patches or array electrodes, should the need arise, and may represent the optimal implant technique under some circumstances. METHODS We studied 29 male patients, aged 29-78 years, who presented with syncope or sustained ventricular tachycardia, and underwent subpectoral defibrillator implantation under general anesthesia or conscious sedation. All devices were third-generation active can systems with biphasic shock capability. Six dual-chamber defibrillators were used. RESULTS Subpectoral implantation was successful in all cases, with an estimated blood loss of 28+/-17 mL and no immediate complications. Except for one patient who developed twiddler's syndrome and ultimately required revision to a subcutaneous pocket, the implant site was tolerated well, and no limitation in the range of motion of the upper limb was observed during 20 months of follow-up. CONCLUSIONS Subpectoral implantation using a lateral approach is technically straightforward and can be applied globally, with modest additional resource and equipment requirements. Familiarity with this approach can maximize the likelihood of successful defibrillator implantation in the electrophysiology laboratory.
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Affiliation(s)
- X F Costeas
- Department of Cardiology, University of Athens School of Medicine, Hippokrateion Hospital, Athens, Greece.
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24
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Abstract
We describe a 23-year-old patient with idiopathic dilated cardiomyopathy in whom an implantable cardioverter defibrillator was implanted via the right external iliac vein. Addition of a subcutaneous patch was required to obtain an adequate safety margin for defibrillation.
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Affiliation(s)
- S L Pinski
- Section of Cardiology, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
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25
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Gold MR. ICD therapy in the new millennium. Cardiol Clin 2000; 18:375-89. [PMID: 10849879 DOI: 10.1016/s0733-8651(05)70147-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Remarkable progress has been made in the 15 years since ICD therapy was approved for human use. The early "shock boxes" had almost no diagnostic capabilities and required thoracotomy for epicardial patch implantation with typical duration of hospitalization of about a week. Pulse-generator longevity was less than 2 years. Modern devices provide detailed information about the morphology and rate of electrocardiographic signals before, during, and after arrhythmia therapy. The down-sizing of pulse generators and improvements in lead design and shock waveforms allow the simplicity of defibrillator implantation to approach that of pacemakers, with defibrillation thresholds comparable with those initially observed with epicardial patches. Despite the marked reduction in size and increase in diagnostic capabilities, device longevity is now longer than 6 years. Routine outpatient ICD implantation is presently feasible and will increase in frequency if ongoing primary prevention trials prove beneficial. Further advances in lead technology and arrhythmia discrimination should increase the efficacy and reliability of therapy. Finally, devices have the capabilities to treat multiple problems in addition to life-threatening ventricular arrhythmias including atrial arrhythmias and congestive heart failure.
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Affiliation(s)
- M R Gold
- Department of Medicine, University of Maryland Medical Center, Baltimore, USA.
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Gold MR, Olsovsky MR, DeGroot PJ, Cuello C, Shorofsky SR. Optimization of transvenous coil position for active can defibrillation thresholds. J Cardiovasc Electrophysiol 2000; 11:25-9. [PMID: 10695457 DOI: 10.1111/j.1540-8167.2000.tb00731.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Lead systems that include an active pectoral pulse generator are now standard for initial defibrillator implantations. However, the optimal transvenous lead system and coil location for such active can configurations are unknown. The purpose of this study was to evaluate the benefit and optimal position of a superior vena cava (SVC) coil on defibrillation thresholds with an active left pectoral pulse generator and right ventricular coil. METHODS AND RESULTS This prospective, randomized study was performed on 27 patients. Each subject was evaluated with three lead configurations, with the order of testing randomized. Biphasic shocks were delivered between the right ventricular coil and an active can alone (unipolar), or an active can in common with the proximal coil positioned either at the right atrial/SVC junction (low SVC) or in the left subclavian vein (high SVC). Stored energies at defibrillation threshold were higher for the single-coil, unipolar configuration (11.2 +/- 6.6 J) than for the high (8.9 +/- 4.2 J) or low (8.5 +/- 4.2 J) SVC configurations (P < 0.01). Moreover, 96% of subjects had low (< or = 15 J) thresholds with the SVC coil in either position compared with 81% for the single-coil configuration. Shock impedance (P < 0.001) was increased with the unipolar configuration, whereas peak current was reduced (P < 0.001). CONCLUSION The addition of a proximal transvenous coil to an active can unipolar lead configuration reduces defibrillation energy requirements. The position of this coil has no significant effect on defibrillation thresholds.
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Affiliation(s)
- M R Gold
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA.
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Cooklin M, Olsovsky MR, Brockman RG, Shorofsky SR, Gold MR. Atrial defibrillation with a transvenous lead: a randomized comparison of active can shocking pathways. J Am Coll Cardiol 1999; 34:358-62. [PMID: 10440146 DOI: 10.1016/s0735-1097(99)00214-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVES The purpose of this study was to compare transvenous atrial defibrillation thresholds with lead configurations consisting of an active left pectoral electrode and either single or dual transvenous coils. BACKGROUND Low atrial defibrillation thresholds are achieved using complex lead systems including coils in the coronary sinus. However, the efficacy of more simple ventricular defibrillation leads with active pectoral pulse generators to defibrillate atrial fibrillation (AF) is unknown. METHODS This study was a prospective, randomized assessment of shock configuration on atrial defibrillation thresholds in 32 patients. The lead system was a dual coil Endotak DSP lead with a left pectoral pulse generator emulator. Shocks were delivered either between the right ventricular coil and an active can in common with the proximal atrial coil (triad) or between the atrial coil and active can (transatrial). RESULTS Delivered energy at defibrillation threshold was 7.1 +/- 6.0 J in the transatrial configuration and 4.0 +/- 4.2 J in the triad configuration (p < 0.005). Moreover, a low threshold (< or = 3 J) was observed in 69% of subjects in the triad configuration but only 47% in the transatrial configuration. Peak voltage and shock impedance were also lowered significantly in the triad configuration. Left atrial size was the only clinical predictor of the defibrillation threshold (r = 0.57, p < 0.002). CONCLUSIONS These results indicate that low atrial defibrillation thresholds can be achieved using a single-pass transvenous ventricular defibrillation lead with a conventional ventricular defibrillation pathway. These data support the development of the combined atrial and ventricular defibrillator system.
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Affiliation(s)
- M Cooklin
- Department of Medicine, University of Maryland Medical System, Baltimore 21201, USA
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Gold MR, Froman D, Kavesh NG, Peters RW, Foster AH, Shorofsky SR. A comparison of pectoral and abdominal transvenous defibrillator implantation: analysis of costs and outcomes. J Interv Card Electrophysiol 1998; 2:345-9. [PMID: 10027120 DOI: 10.1023/a:1009756520054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Traditionally cardioverter-defibrillator implantation was performed by surgeons under general anesthesia. However, with advances in lead and pulse generator technology, the surgical implantation technique has been simplified and routine pectoral pulse generator placement without general anesthesia is now possible. To assess the economic benefit of pectoral implantation, we analyzed 43 consecutive initial transvenous defibrillator implantations. The patients were grouped according to whether the implant was abdominal by a surgeon in the operating room (n = 23) or pectoral by an electrophysiologist in a laboratory (n = 20). The duration of hospitalization was significantly longer in the operating room than in the laboratory group (8.1 +/- 3.4 vs 5.8 +/- 2.4 days, p = 0.01), which was due primarily to the postoperative stay which averaged 1.9 days longer. Total costs were $40,274 +/- 6,861 for the operating room cohort and $32,546 +/- 3,634 for the lab group (p < 0.001). This reduction was due to a 32% lowering of professional costs and an 18% lowering of facility costs. We conclude that pectoral defibrillator implantation is cost effective and results in significant reductions of hospital stay.
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Affiliation(s)
- M R Gold
- Department of Medicine, University of Maryland School of Medicine, Baltimore, USA.
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Tokano T, Pelosi F, Flemming M, Horwood L, Souza JJ, Zivin A, Knight BP, Goyal R, Man KC, Morady F, Strickberger SA. Long-term evaluation of the ventricular defibrillation energy requirement. J Cardiovasc Electrophysiol 1998; 9:916-20. [PMID: 9786072 DOI: 10.1111/j.1540-8167.1998.tb00132.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Defibrillation energy requirements in patients with nonthoracotomy defibrillators may increase within several months after implantation. However, the stability of the defibrillation energy requirement beyond 1 year has not been reported. The purpose of this study was to characterize the defibrillation energy requirement during 2 years of clinical follow-up. METHODS AND RESULTS Thirty-one consecutive patients with a biphasic nonthoracotomy defibrillation system underwent defibrillation energy requirement testing using a step-down technique (20, 15, 12, 10, 8, 6, 5, 4, 3, 2, and 1 J) during defibrillator implantation, and then 24 hours, 2 months, 1 year, and 2 years after implantation. The mean defibrillation energy requirement during these evaluations was 10.9+/-5.5 J, 12.3+/-7.3 J, 11.7+/-5.6 J, 10.2+/-4.0 J, and 11.7+/-7.4 J, respectively (P = 0.4). The defibrillation energy requirement was noted to have increased by 10 J or more after 2 years of follow-up in five patients. In one of these patients, the defibrillation energy requirement was no longer associated with an adequate safety margin, necessitating revision of the defibrillation system. There were no identifiable clinical characteristics that distinguished patients who did and did not develop a 10-J or more increase in the defibrillation energy requirement. CONCLUSION The mean defibrillation energy requirement does not change significantly after 2 years of biphasic nonthoracotomy defibrillator system implantation. However, approximately 15% of patients develop a 10-J or greater elevation in the defibrillation energy requirement, and 3% may require a defibrillation system revision. Therefore, a yearly evaluation of the defibrillation energy requirement may be appropriate.
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Affiliation(s)
- T Tokano
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0022, USA
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Olsovsky MR, Pelini MA, Shorofsky SR, Gold MR. Temporal stability of defibrillation thresholds with an active pectoral lead system. J Cardiovasc Electrophysiol 1998; 9:240-4. [PMID: 9554728 DOI: 10.1111/j.1540-8167.1998.tb00908.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Monophasic defibrillation thresholds rise over time with a variety of lead systems. These chronic changes are attenuated or eliminated by biphasic waveforms, although the effect appears dependent upon the lead system. With the downsizing of pulse generator size to allow for routine pectoral implantation, active can lead systems have now become standard. However, the temporal stability of such lead systems has not been evaluated previously. METHODS AND RESULTS This study was a prospective assessment of the changes of active pectoral defibrillation thresholds over time. Thresholds were measured at implant, predischarge, and at a mean follow-up of 50 days in 46 patients with a uniform testing protocol and shock polarity. The lead system was a dual-coil Endotak DSP lead with an active pectoral pulse generator. Defibrillation thresholds were 9.9+/-5.5 J at implantation, 8.5+/-6.0 J predischarge, and 7.6+/-5.5 J at follow-up (ANOVA, P = 0.007). Moreover, only two patients developed an increased threshold > 5 J, and no patient had an inadequate safety margin at follow-up. CONCLUSION These results indicate that active pectoral defibrillation thresholds are stable over the first 2 months postimplantation and question the need for routine serial defibrillation threshold testing.
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Affiliation(s)
- M R Olsovsky
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA
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Olsovsky MR, Hodgson DM, Shorofsky SR, Kavesh NG, Gold MR. Effect of biphasic waveforms on transvenous defibrillation thresholds in patients with coronary artery disease. Am J Cardiol 1997; 80:1098-100. [PMID: 9352990 DOI: 10.1016/s0002-9149(97)00615-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study is a prospective, randomized comparison of monophasic and biphasic defibrillation thresholds in 19 patients with a single transvenous lead. Despite using reverse polarity and optimal tilts for the monophasic waveform, the defibrillation threshold was reduced with biphasic shocks from 15.8 +/- 11.3 to 11.5 +/- 6.1 (p <0.05) with comparable reductions of leading edge voltage and current.
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Affiliation(s)
- M R Olsovsky
- Department of Medicine, University of Maryland Medical System, Baltimore 21201, USA
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