Response to Letter Regarding Article, “Necessity for Surgical Revision of Chronically Implanted Defibrillator Leads: Causes and Management”
We thank Dr Kleemann and Dr Seidl for their interest in our article recently published in Circulation.1 They correctly point out that only 13 implantable cardioverter-defibrillator (ICD) leads (34%) were replaced, although 9 leads had lead fractures and 10 leads had insulation defects. We agree that in these cases a risk exists of progression of the lead defect involving the entire ICD lead. For safety reasons, we therefore replaced all ICD leads found to have a problem with the pace/sense part distal to the bifurcation or trifurcation of the ICD lead. As stated in our article, we only added a pace/sense lead if a fracture (n=3) or insulation defect (n=4) was visible in the pace/sense part proximal to the bi- or trifurcation. In all other cases of fracture or insulation defects, the entire ICD lead was replaced. In total, 18 cases (72%), which were treated with an additional pace/sense lead, had no signs of lead fracture or insulation defects.
The ICD leads were then monitored by regular impedance measurements of the high voltage parts, either with subthreshold or low-energy testing during routine follow-up. As described in our article, 3 patients with old ICD leads left in place experienced another lead malfunction. Two of the cases were due to sensing issues and the third to a lead fracture.
Finally, Dr Kleemann and Dr Seidl claim that impedance measurements of the high voltage part may not be completely reliable and point out that in their series 2% of lead defects were only detected during elective ICD generator change.2 They do not describe what these lead defects consisted of. In fact, they may have been due to lead injury secondary to surgery itself. We see no reason to doubt that noninvasive impedance measurements of the high voltage part are sufficient to follow-up with these leads.
Dr Sticherling and Dr Zabel are consultants for Medtronik, Boston Scientific, and Biotronik. Dr Schaer has received honoraria from Boston Scientific. Dr Oswald is a consultant for Medtronic, Boston Scientific, Biotronik, and St. Jude Medical.
Eckstein J, Koller MT, Zabel M, Kalusche D, Schaer BA, Osswald S, Sticherling C. Necessity for surgical revision of defibrillator leads implanted long-term: causes and management. Circulation. 2008; 117: 2727–2733.
Kleemann T, Becker T, Doenges K, Vater M, Senges J, Schneider S, Saggau W, Weisse U, Seidl K. Annual rate of transvenous defibrillation lead defects in implantable cardioverter-defibrillators over a period of >10 years. Circulation. 2007; 115: 2474–2480.