1
|
Tripathi R, Gubran C, Jeavons C. Automatic adjustment of ventricular antitachycardia pacing and individualized device therapy. HeartRhythm Case Rep 2021; 8:171-175. [PMID: 35492849 PMCID: PMC9039548 DOI: 10.1016/j.hrcr.2021.11.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Rajiv Tripathi
- Gloucestershire Royal Hospital, Gloucester, United Kingdom
- Address reprint requests and correspondence: Dr Rajiv Tripathi, Gloucestershire Royal Hospital, Great Western Rd, Gloucester GL1 3NN, UK.
| | | | | |
Collapse
|
2
|
Sattar A, Inbar S. Ventricular fibrillation induced by high-output ICD shock: report of cases and review of literature. BMJ Case Rep 2017; 2017:bcr-2017-220098. [DOI: 10.1136/bcr-2017-220098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
3
|
Burri H, Moretti F, Meyer P. Low-energy cardioversion of ventricular tachycardia: When less is more. Indian Pacing Electrophysiol J 2017; 17:44-47. [PMID: 29072992 PMCID: PMC5405749 DOI: 10.1016/j.ipej.2017.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 02/13/2017] [Indexed: 11/23/2022] Open
Abstract
Herein we report the case of a patient who was admitted in ventricular tachycardia after having received multiple ineffective (and sometimes pro-arrhythmic) high-energy internal shocks from his ICD and who was finally successfully treated by a commanded low-energy internal cardioversion of 0.6 J. This article revisits the use of low-energy shocks and discusses their electrophysiogical mechanisms and clinical implications.
Collapse
Affiliation(s)
- Haran Burri
- Cardiology Department, Geneva University Hospital, Geneva, Switzerland.
| | - Francesco Moretti
- Cardiology Department, Geneva University Hospital, Geneva, Switzerland
| | - Philippe Meyer
- Cardiology Department, Geneva University Hospital, Geneva, Switzerland
| |
Collapse
|
4
|
Steffel J. [Redetection of tachycardia in severe ventricular undersensing]. Herzschrittmacherther Elektrophysiol 2016; 27:240-243. [PMID: 27459975 DOI: 10.1007/s00399-016-0445-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 06/06/2023]
Abstract
In a 50-year-old patient with arrhythmogenic right ventricular cardiomyopathy (ARVC) and implantable cardioverter defibrillator (ICD) two shock discharges occurred after several ineffective attempts with antitachycardia pacing. The analysis of the stored electrograms shows a peculiarity of shocks with low energy, a problem of ICD therapy in ARVC, and the impact of committed shocks as opposed to non-committed shocks.
Collapse
Affiliation(s)
- Jan Steffel
- Kardiologie/Rhythmologie, Universitäres Herzzentrum Zürich, Universitätsspital Zürich, Rämistr. 100, 8091, Zürich, Schweiz.
| |
Collapse
|
5
|
Toniolo M, Figueroa J, Castrejòn-Castrejòn S, Merino JL. Induction of tachycardia confined within a pulmonary vein by electrical cardioversion of atrial fibrillation: Is it proof of reentry? HeartRhythm Case Rep 2015; 1:225-228. [PMID: 28491554 PMCID: PMC5419328 DOI: 10.1016/j.hrcr.2015.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
|
6
|
Tenma T, Yokoshiki H, Mizukami K, Mitsuyama H, Watanabe M, Sasaki R, Maeno M, Matsui Y, Tsutsui H. Predictors and Proarrhythmic Consequences of Inappropriate Implantable Cardioverter-Defibrillator Therapy. Circ J 2015; 79:1920-7. [PMID: 26104029 DOI: 10.1253/circj.cj-15-0306] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Despite the benefits of implantable cardioverter-defibrillator (ICD) therapy, inappropriate shocks can lead to multiple adverse effects. The aim of this study was to clarify the predictors of inappropriate ICD shocks and their proarrhythmic consequences. METHODS AND RESULTS We retrospectively studied 316 consecutive patients who underwent ICD implantation from December 2000 to December 2011. Of them, 70 (22%) experienced inappropriate ICD shocks without proarrhythmia requiring some intervention; 2 patients (0.6%) had proarrhythmic inappropriate ICD therapy by antitachycardia pacing (ATP), thereby calculated to be 0.18% of patients per year. However, they did not have syncope from this inappropriate ATP. Multivariate analysis identified younger age (≤56 years: hazard ratio [HR] 1.68, 95% confidence interval [CI] 1.02-2.77, P=0.043), paroxysmal atrial fibrillation (HR 3.00, 95% CI 1.64-5.31, P=0.0002), stroke (HR 2.23, 95% CI 1.11-4.47, P=0.024), and no diuretic use (HR 1.72, 95% CI 1.03-2.93, P=0.039) as independent predictors of the occurrence of inappropriate ICD shocks. CONCLUSIONS Young age, paroxysmal atrial fibrillation, stroke, and no use of diuretics were independently associated with inappropriate ICD shocks. Proarrhythmic inappropriate ICD therapy was observed with an annual incidence of 0.18% by ATP.
Collapse
Affiliation(s)
- Taro Tenma
- Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine
| | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Can I, Tholakanahalli V. “Atrial torsades de pointes” Induced by Low-Energy Shock From Implantable-Cardioverter Defibrillator. Indian Pacing Electrophysiol J 2013; 13:194-9. [PMID: 24130431 PMCID: PMC3775325 DOI: 10.1016/s0972-6292(16)30674-x] [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: 10/31/2022] Open
Abstract
A 58 year-old-patient developed an episode of polymorphic atrial tachycardia which looked like "atrial torsades de pointes" after a 5J shock from implantable cardioverter defibrillator.
Collapse
|
8
|
LAWO THOMAS, SCHRADER JÜRGEN, BUDDENSIEK MICHAEL, SCHWEIKA OLIVER, MÜGGE ANDREAS, BÖSCHE LEIFI. Termination of Ventricular Tachycardia by Far-Field Stimulation in Humans: A Feasibility Study. Pacing Clin Electrophysiol 2010; 33:1540-7. [DOI: 10.1111/j.1540-8159.2010.02891.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
Paleiron N, Pegorie A, Nguyen BV, Giacardi C, Commandeur D, Danguy des Déserts M, Ould-Ahmed M. Must we always follow the instructions of automated external defibrillators? Intensive Care Med 2009; 36:723-4. [PMID: 20012935 DOI: 10.1007/s00134-009-1731-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2009] [Indexed: 12/01/2022]
|
10
|
Abstract
Implantable cardioverter-defibrillator (ICD) interventions have the potential to be proarrhythmogenic. New arrhythmias can occur in the setting of clinically appropriate therapies, as well as during a cardiac rhythm for which therapy is not intended. Cardioversion/defibrillation therapies, antitachycardia pacing, and antibradycardia pacing are potential triggers for the development of new arrhythmias. Newer ICDs allow better recognition and interpretation of the arrhythmias that are induced by delivered therapies. Two cases of ICD-induced proarrhythmias are described. Based on the course of these patients and review of previous reports, proarrhythmic effects of ICD interventions along with prevention and management strategies are discussed.
Collapse
Affiliation(s)
- F Duru
- Department of Internal Medicine, University Hospital of Zurich, Switzerland
| | | |
Collapse
|
11
|
Lawo T, Deneke T, Schrader J, Danilovic D, Wenzel B, Buddensiek M, Muegge A. A comparison of chronaxies for ventricular fibrillation induction, defibrillation, and cardiac stimulation: unexpected findings and their implications. J Cardiovasc Electrophysiol 2008; 20:307-14. [PMID: 19175850 DOI: 10.1111/j.1540-8167.2008.01319.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION A low-energy (<or= 4 J) cardioversion shock (LEC) either terminates reentrant ventricular tachycardia (VT) or accelerates it to ventricular fibrillation (VF). Optimization of the duration and amplitude of LEC shocks could improve the success rate of VT termination without VF induction. METHODS AND RESULTS In order to learn how LEC shocks may be optimized, we used an animal model to compare the strength-duration curve for VF induction and the strength-duration curve for cardiac stimulation via the shock coil. Conventional implantable cardioverter-defibrillator (ICD) leads were implanted in 12 narcotized pigs from 20 kg to 25 kg in weight. Stimulation, VF induction, and defibrillation pulses were delivered by custom-designed stimulators at preset pulse durations and amplitudes. The corresponding hyperbolic strength-duration curves were constructed using the least-squares fit method and averaged for all the animals. The mean chronaxie for stimulation via the shock coil of 0.23 ms was significantly shorter than both defibrillation (4.8 ms) and VF induction (3.1 ms) chronaxie values. At a shock duration of 0.3 ms or less, the mean VF-induction threshold amplitude exceeded 300 V. CONCLUSION It may be reasonable to study whether LEC pulses from 0.25 ms to 0.30 ms in duration and up to 250 V in amplitude would increase therapeutic yield in VT termination without VF induction in humans. Contrary to the current belief, the discrepancy between defibrillation and stimulation chronaxie is not caused by different electrode size. We postulate that the time constant of the fast sodium channel reactivation may be the underlying reason.
Collapse
Affiliation(s)
- Thomas Lawo
- Medical Clinic II (Cardiology), BG University Hospital Bergmannsheil, Bochum, Germany.
| | | | | | | | | | | | | |
Collapse
|
12
|
Varriale P, Leonardi M. Polymorphic ventricular tachycardia in the coronary care unit. Heart Lung 2006; 35:283-9. [PMID: 16863901 DOI: 10.1016/j.hrtlng.2005.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Accepted: 12/05/2005] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To describe the clinical experience of patients with polymorphic ventricular tachycardia (PMVT) in a hospital setting. METHODS A 2-year prospective, observational study of patients with symptomatic and asymptomatic PMVT admitted to the coronary care unit of a community medical center. Electrocardiograms were reviewed for a pattern diagnostic of PMVT, and the QTc interval of the baseline ECG was determined. Etiologic factors, management, and clinical outcomes were also analyzed. RESULTS The study included 27 patients (13 men) with a mean age of 66.6 +/- 10 years. Fourteen patients had a prolonged QTc interval >or=520 ms (group A), and 10 patients had a normal QTc interval <or=440 ms (group B). Acute hypokalemia (n = 7) in the setting of underlying heart disease was the principal cause of the acquired QT syndrome; other causally related factors included severe bradycardia and the proarrhythmic effect of drugs. Acute myocardial infarction (n = 6) was the principal cause of PMVT associated with a normal QTc interval; other causal factors included right ventricular cardiomyopathy and the proarrhythmic effect of electrical cardioversion. Eight patients (group C) had brief runs of asymptomatic nonsustained PMVT, which recurred in 5 patients as symptomatic sustained PMVT despite appropriate treatment. Cardiac arrest (63%) requiring emergency defibrillation was the predominant clinical presentation irrespective of the QT interval. Four patients (15%) died, but only 2 owing to refractory PMVT/VF. CONCLUSION PMVT with or without QTc prolongation is a sporadic tachyarrhythmia that has frequent malignant potential for cardiac arrest. Successful management mandates emergency defibrillation for cardiac arrest and other appropriate measures for suppression of PMVT. The prognosis of PMVT is improved when the cause is correctly identified and promptly treated.
Collapse
Affiliation(s)
- Philip Varriale
- Division of Cardiology, Cabrini Medical Center of New York, New York, New York, USA
| | | |
Collapse
|
13
|
Washizuka T, Chinushi M, Hatada K, Kasai H, Ohhira K, Furushima H, Aizawa Y. Both low and high energy cardioversion induced accelerated ventricular tachycardia in a patient treated with an implantable cardioverter defibrillator. JAPANESE HEART JOURNAL 1999; 40:665-9. [PMID: 10888386 DOI: 10.1536/jhj.40.665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A 72-year old male with an old myocardial infarction who had drug-refractory ventricular tachyarrhythmias received an implantable cardioverter-defibrillator (ICD). The patient did not take his prescribed beta-blocking agent for two days, following which he experienced six discrete shocks for spontaneous VT while riding his bicycle. Both 5J and 30J cardioversions were ineffective at terminating the VT and accelerated VT developed following the shocks. After admission, an electrophysiological study was performed while he was taking the beta-blocking agent, both low and high energy cardioversions reproducibly terminated the clinical VT without showing any accelerated rhythm. These findings suggest that the increase in sympathetic discharge may enhance the proarrhythmic potential of ICDs.
Collapse
Affiliation(s)
- T Washizuka
- First Department of Internal Medicine, Niigata University School of Medicine, Asahimachi, Japan
| | | | | | | | | | | | | |
Collapse
|
14
|
Mitrani RD, Miles WM, Klein LS, Zipes DP. Phenylephrine increases T wave shock energy required to induce ventricular fibrillation. J Cardiovasc Electrophysiol 1998; 9:34-40. [PMID: 9475575 DOI: 10.1111/j.1540-8167.1998.tb00864.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Previous reports in experimental models have suggested that ventricular fibrillation threshold (VFT) can be changed by manipulating cardiac neural tone using agents such as phenylephrine. The purpose of this study was to determine whether phenylephrine increased the energy required to induce VF in humans undergoing such induction using DC energy applied to the T wave. METHODS AND RESULTS In this prospective investigation, 18 consecutive patients with previously implanted cardioverter defibrillators had induction of VF by placing DC monophasic shocks into the T wave coupled 310 msec after the eighth paced ventricular complex at 400 msec. The T wave shock energy was titrated from 0.2 to 12 J until sustained VF or ventricular tachycardia was induced. Phenylephrine was infused either before the first or second VF induction in a randomized fashion to increase systolic blood pressure by more than 20 mmHg. The mean energy required to induce VF was 1.1 J at baseline and increased to 1.7 J during phenylephrine infusion (P = 0.036). The mean arterial pressure increased from 88 to 114 mmHg (P < 0.001), and the mean sinus cycle length increased from 850 to 1070 msec (P < 0.001). Ten of 13 (77%) patients with sinus cycle length prolongation had increased energy requirements to induce VF compared with only 1 of 5 patients (20%) without sinus cycle length prolongation (P < 0.05). CONCLUSION Phenylephrine increases VFT in humans presumably by reflex activation of the baroreceptors decreasing sympathetic and/or increasing parasympathetic cardiac efferent effects.
Collapse
Affiliation(s)
- R D Mitrani
- Krannert Institute of Cardiology, Indiana School of Medicine, Indiana University Medical Center, Indianapolis, USA
| | | | | | | |
Collapse
|
15
|
Florin TJ, Weiss DN, Peters RW, Shorofsky SR, Gold MR. Induction of atrial fibrillation with low-energy defibrillator shocks in patients with implantable cardioverter defibrillators. Am J Cardiol 1997; 80:960-2. [PMID: 9382019 DOI: 10.1016/s0002-9149(97)00556-0] [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: 02/05/2023]
Abstract
In a population of 151 consecutive patients who received an implantable cardioverter defibrillator, we found that atrial fibrillation was induced by low-energy shocks in 19% and was most common in patients with lead systems that included a right atrial electrode. Our finding that there was a fixed relation between the energy required to fibrillate (< or = 3 J) and defibrillate (> 3 J) suggests the presence of an upper limit of vulnerability in the human atrium.
Collapse
Affiliation(s)
- T J Florin
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA
| | | | | | | | | |
Collapse
|
16
|
Ellenbogen KA, Epstein AE, Wood MA, Stambler BS, Kay GN, Plumb VJ, Voshage-Stahl L, Hull ML. Are more complex implantable cardioverter defibrillators associated with an increased mortality? Lessons learned from clinical trials. Am J Cardiol 1997; 80:958-60. [PMID: 9382018 DOI: 10.1016/s0002-9149(97)00555-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We compared 1-year survival in patients receiving implantable cardioverter defibrillators (ICDs) that provide only shock therapy with more advanced ICDs that provide antitachycardia pacing, bradycardia pacing, low-energy cardioversion, and advanced detection algorithms. Outcome in patients with advanced-generation ICD systems was similar or improved compared with outcome in patients receiving ICDs with only monophasic shock.
Collapse
Affiliation(s)
- K A Ellenbogen
- Department of Medicine, Medical College of Virginia and the McGuire VA Medical Center, Richmond 23298-0053, USA
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Sudden Death Despite ICD Therapy: Why Does It Happen? ACTA ACUST UNITED AC 1996. [DOI: 10.1007/978-1-4615-6345-7_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
18
|
Abstract
The implantable cardioverter-defibrillator (ICD) is remarkably effective in preventing sudden cardiac death in high-risk patients, but it also has the capacity to provoke or worsen cardiac arrhythmias. Tachyarrhythmias or bradyarrhythmias may result from the delivery of antitachycardia or antibradycardia therapies by tiered-therapy defibrillators. This proarrhythmia, although rarely fatal, increases the morbidity associated with defibrillator therapy. Proarrhythmia is related as much to suboptimal programming as to technical limitations of the device. The proarrhythmic potential of ICD therapy can be minimized by tailoring the "electrical prescription" according to characteristics of the clinical arrhythmia and individual ICD idiosyncrasies.
Collapse
Affiliation(s)
- S L Pinski
- Department of Cardiology, Cleveland Clinic Foundation, OH, USA
| | | |
Collapse
|
19
|
Brewer JE, Tvedt MA, Adams TP, Kroll MW. Low voltage shocks have a significantly higher tilt of the internal electric field than do high voltage shocks. Pacing Clin Electrophysiol 1995; 18:214. [PMID: 7724402 DOI: 10.1111/j.1540-8159.1995.tb02507.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Typically, an implantable cardioverter defibrillator (ICD) uses a cardioversion shock that is a lower voltage pulse of the same morphology and tilt as its defibrillation pulse. We investigated the internal electric field resulting from an ICD low voltage shock to determine whether its field characteristics matched those of the internal electric field of a high voltage shock. We attached epicardial patch electrodes, for shock delivery, to five fresh pig hearts placed in a diluted, heparinized saline bath. We inserted two plunge electrodes into the myocardium to measure an internal voltage proportional to the electric field. Monophasic 20-msec shocks, from a 140-microF capacitor, ranging from 0.1-30 joules, were delivered through the patches. We measured the current, external voltage, and internal voltage every 0.1 msec throughout the duration of a shock. For each shock, we calculated the time point that represented the 65% tilt position as measured across the patch electrodes. At this 65% tilt time position, we measured the pulse widths and calculated the internal tilt from the internal voltage. We found that the initial internal voltage for the 30-joule shock was 173 +/- 40 volts compared to 10 +/- 2 volts for the 0.1-joule shock. Similarly, we found that the final internal voltage for the 30-joule shock was 56 +/- 14 volts compared to 2 +/- 1 volts for the 0.1-joule shock. Thus, the internal tilt for the 30-joule shock was 68 +/- 1% versus 82 +/- 3% for the 0.1-joule shock (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J E Brewer
- Angeion Corporation, Plymouth, Minnesota 55447
| | | | | | | |
Collapse
|
20
|
Lehmann MH, Thomas A, Nabih M, Steinman RT, Fromm BS, Shah M, Norsted SW. Sudden death in recipients of first-generation implantable cardioverter defibrillators: analysis of terminal events. Participating investigators. J Interv Cardiol 1994; 7:487-503. [PMID: 10155197 DOI: 10.1111/j.1540-8183.1994.tb00485.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Clinical factors and terminal events associated with sudden death in 51 patients were analyzed from among a multicenter experience of 864 recipients of first generation automatic implantable cardioverter defibrillator (AICD) devices (single zone, committed, monophasic pulse with > or = 1 epicardial patch electrode) during the period May 1982-February 1988. For these 51 patients, mean age was 58 years and atherosclerotic heart disease was present in 84%, with a history of ventricular fibrillation (VF) in 61%, and inducible sustained ventricular tachycardia (VT) in 84%; mean left ventricular ejection fraction was 0.26. Nearly 80% experienced one or more appropriate AICD shocks during the median 9 month (range 0-46 months) period prior to death. Of 30 monitored deaths, the first documented terminal rhythm was VF in 12 (40%), VT in 8 (27%), and asystole or electromechanical dissociation in the remaining 10 (33%). Shocks were documented during terminal events in 21 (66%) of 32 witnessed cases of sudden death with activated devices. The proportion of monitored or witnessed sudden deaths that were known or presumed to be tachyarrhythmic (based on terminal VT, VF, or shocks) ranged from 69% (11/16 cases with activated/nondepleted devices and a defibrillation threshold [DFT] < or = 20 J) to 81% (29/36 cases on intention-to-treat basis). Of 27 patients with known or presumed sudden tachyarrhythmic death, the AICD had been deactivated prior to death in 4 (15%); activated, but depleted in 4 (15%); activated/nondepleted, but with DFT of 25 J in 4 (15%); and activated/nondepleted, but without DFT testing in 4 (15%). The remaining 11 (41%) known or presumed sudden tachyarrhythmic deaths occurred in patients with activated/nondepleted devices and DFT < or = 20 J; however, definite or suspected contributory factors (e.g., hematoma under epicardial patch, generator component failure, or drug-induced DFT rise) could be identified in 6 (55%) of 11 cases. Thus, in this first-generation AICD experience: 1) most sudden deaths occurred on the basis of a known or presumed tachyarrhythmia; and 2) an understanding of apparent "failure" of ICD therapy could often be gained through an integrated analysis of associated clinical factors and management practices, as well as device "hardware" function. These observations are likely to remain relevant, even with respect to newer generation ICDs.
Collapse
Affiliation(s)
- M H Lehmann
- Division of Cardiology/Department of Medicine, Harper Hospital, Wayne State University School of Medicine, Detroit, MI, USA
| | | | | | | | | | | | | |
Collapse
|