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To the Editor—Response
LETTERS TO THE EDITOR To the Editor: In the last issue of Heart Rhythm, Hauser et al1 report that the Sprint Fidelis 6949 high-voltage lead appears to be prone to early failure. We have also seen a higher than expected rate of failure of the single-coil variety of the Sprint Fidelis implantable cardioverter-defibrillator (ICD; Medtronic, Inc., Minneapolis, MN) lead that is implanted at our center (model 6931). Our experience suggests there may be a particular concern in younger physically active patients. We have implanted 266 Sprint Fidelis 6931 ICD leads at our center over a 30-month period and have seen three lead failures resulting in inappropriate shocks. The implant procedures, by two experienced implanters, were uncomplicated. To date, one has been confirmed as being due to distal conductor fracture. All three patients were young (mean age 35 years) and had physically active hobbies. The failures were relatively early (mean 17 months). While the overall failure rate for the lead is 1.1%, the failure rate is 7.8% among patients ⬍50 years of age. The population of patients in whom we have seen failures is compatible with a hypothesis that vigorous cardiac motion and/or physical activity, that is, patient-specific factors, may have accelerated any inherent tendency to fatigue-based failure of components. Archana Rao, MRCP Jay Wright, MD, Consultant Cardiologist Johan Waktare, FRCP, Consultant Cardiologist/ Electrophysiologist Derick Todd, MD, Consultant Cardiologist/ Electrophysiologist Cardiothoracic Centre Liverpool, United Kingdom
Reference 1.
Hauser RG, Kallinen LM, Almquist A, Gornick C, Katsiyannis W. Early failure of a small-diameter high voltage implantable cardioverter-defibrillator lead. Heart Rhythm 2007;4:892– 896.
To the Editor—Response: Since the publication of our paper in Heart Rhythm,1 we and others have experienced additional Sprint Fidelis lead failures, and more adverse clinical events have been posted on the U.S. Food and Drug Administration’s Web site (www.fda.gov/cdrh/maude.html). The observation by Rao and colleagues is important because it suggests that younger patients may be at higher risk for lead failure than less vigorous adults. Such patients are often those who have genetic heart disease and whose prognosis is good if sudden cardiac death can be
prevented by a normally functioning implantable cardioverterdefibrillator. Studies are needed to identify the variables that predict Sprint Fidelis lead failure to facilitate patient management. Meanwhile, we encourage physicians not to implant this lead in any patient until the failure mechanism is understood and remedied by the manufacturer. Robert G. Hauser, MD Linda M. Kallinen, BS Adrian K. Almquist, MD Charles C. Gornick, MD William T. Katsiyiannis, MD Minneapolis Heart Institute Minneapolis, Minnesota
Reference 1.
Hauser RG, Kallinen LM, Almquist AK, Gornick CC, Katsiyiannis WT. Early failure of a small-diameter high-voltage implantable cardioverter-defibrillator lead. Heart Rhythm 2007;4:892– 896.
To the Editor: In the July 2007 print edition (online April 2007) of the Journal, Hauser et al1 reported the higher than expected early failure rate of the Sprint Fidelis implantable cardioverter defibrillator lead (model 6949, Medtronic, Inc.) and recommended limiting its use until the issue was resolved. Over the last two and a half years, 180 Sprint Fidelis model 6931 (single coil) leads have been implanted and 5 have failed after an average of 16 months (range 13–19 months). In one case the lead malfunction was detected on routine device interrogation (impedance rise and electrical noise on the pace/sense channel). Three other patients presented with multiple inappropriate shocks with the same findings. The fifth patient died after the sixth and final delivery of a run of inappropriate shocks induced ventricular fibrillation (VF) because the lead was sensing electrical noise, inappropriately interpreted as VF, and all six shocks of the treatment episode were delivered during sinus rhythm. The device detected true VF after the final shock but no further therapy was delivered as the treatment course was complete. All 5 of our lead failures occurred in young patients (mean age 34, range 23– 45 years). Our experience with the single coil model (6931) Sprint Fidelis lead confirms it is also associated with unacceptably high rates of early failure and we, too, urge all implanting physicians to use alternative leads pending further information from the manufacturer.
1547-5271/$ -see front matter © 2008 Heart Rhythm Society. All rights reserved.
Dr Andrei Catanchin, MBBS Dr Lisa Anderson, MD Ms Sue Jones Dr David Ward, MD
Reference 1.
Hauser RG, Kallinen LM, Almquist A, Gornick C, Katsiyannis W. Early failure of a small-diameter high voltage implantable cardioverter-defibrillator lead. Heart Rhythm 2007;4:892– 896.
To the Editor—Response: Since the publication of our paper in Heart Rhythm,1 we and others have experienced additional Sprint Fidelis lead failures, and more adverse clinical events have been posted on the U.S. Food and Drug Administration’s Web site (www.fda.gov/cdrh/maude.html). The observation by Rao and colleagues is important because it suggests that younger patients may be at higher risk for lead failure than less vigorous adults. Such patients are often those who have genetic heart disease and whose prognosis is good if sudden cardiac death can be
prevented by a normally functioning implantable cardioverterdefibrillator. Studies are needed to identify the variables that predict Sprint Fidelis lead failure to facilitate patient management. Meanwhile, we encourage physicians not to implant this lead in any patient until the failure mechanism is understood and remedied by the manufacturer. Robert G. Hauser, MD Linda M. Kallinen, BS Adrian K. Almquist, MD Charles C. Gornick, MD William T. Katsiyiannis, MD Minneapolis Heart Institute Minneapolis, Minnesota
Reference 1.
Hauser RG, Kallinen LM, Almquist AK, Gornick CC, Katsiyiannis WT. Early failure of a small-diameter high-voltage implantable cardioverter-defibrillator lead. Heart Rhythm 2007;4:892– 896.
To the Editor: In the July 2007 print edition (online April 2007) of the Journal, Hauser et al1 reported the higher than expected early failure rate of the Sprint Fidelis implantable cardioverter defibrillator lead (model 6949, Medtronic, Inc.) and recommended limiting its use until the issue was resolved. Over the last two and a half years, 180 Sprint Fidelis model 6931 (single coil) leads have been implanted and 5 have failed after an average of 16 months (range 13–19 months). In one case the lead malfunction was detected on routine device interrogation (impedance rise and electrical noise on the pace/sense channel). Three other patients presented with multiple inappropriate shocks with the same findings. The fifth patient died after the sixth and final delivery of a run of inappropriate shocks induced ventricular fibrillation (VF) because the lead was sensing electrical noise, inappropriately interpreted as VF, and all six shocks of the treatment episode were delivered during sinus rhythm. The device detected true VF after the final shock but no further therapy was delivered as the treatment course was complete. All 5 of our lead failures occurred in young patients (mean age 34, range 23– 45 years). Our experience with the single coil model (6931) Sprint Fidelis lead confirms it is also associated with unacceptably high rates of early failure and we, too, urge all implanting physicians to use alternative leads pending further information from the manufacturer.
1547-5271/$ -see front matter © 2008 Heart Rhythm Society. All rights reserved.
Dr Andrei Catanchin, MBBS Dr Lisa Anderson, MD Ms Sue Jones Dr David Ward, MD