LETTERS TO THE EDITOR
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Charles Swerdlow, MD
Cedars–Sinai Medical Center, 8635 West Third Street, Suite 1190 W, Los Angeles, CA 90048
(Email: swerdlow{at}ucla.edu).
I thank Dr. Kantharia for his interest in our recent paper (1). Identifying the optimal patient-specific implantable cardioverter-defibrillator (ICD) system and its programming, without the need for either ventricular fibrillation (VF) or shocks, is a major research goal. The patients reported by Dr. Kantharia both emphasize the importance of this goal and illustrate poignantly that it remains beyond our grasp.
The first case highlights the unmet need of developing effective treatment for life-threatening, post-VF electromechanical dysfunction (EMD) (2,3). Paradoxically, defibrillation testing may have saved this patient's life: If VF had occurred as an outpatient, either defibrillation would have failed or the postshock rhythm would have been lethal EMD. To the best of my knowledge, fatal postshock EMD has not been reported after an inappropriate shock. Thus, postshock EMD probably is caused by a combination of VF and shocks, often prolonged VF and multiple shocks.
The second patient died from failed defibrillation with an untested ICD system. This case illuminates the need for a shockless method of assessing ventricular defibrillation efficacy, or at least a method that minimizes the risk of thromboembolism from atrial cardioversion. One consideration is continuous rapid atrial stimulation during ventricular defibrillation or vulnerability testing.
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References
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1. Swerdlow CD. Reappraisal of implant testing of implantable cardioverter-defibrillators J Am Coll Cardiol 2004;44:92-94.[Free Full Text]
2. Mitchell LB, Pineda EA, Titus JL, Bartosch PM, Benditt DG. Sudden death in patients with implantable cardioverter-defibrillators: the importance of post-shock electromechanical dissociation J Am Coll Cardiol 2002;39:1323-1328.[Abstract/Free Full Text]
3. Rosborough J, Deno C. Electrical therapy for pulseless electrical activity (abstr) Pacing Clin Electrophysiol 2000;23:591.
Related Article
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Defibrillation thresholds testing of implantable cardioverter-defibrillators at implantation
- Bharat K. Kantharia
J. Am. Coll. Cardiol. 2005 45: 468.
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