{"id":30515,"date":"2012-07-19T12:23:41","date_gmt":"2012-07-19T16:23:41","guid":{"rendered":"http:\/\/blogs.nejm.org\/cardioexchange\/?post_type=voices&p=30515"},"modified":"2012-07-19T12:43:38","modified_gmt":"2012-07-19T16:43:38","slug":"new-icd-lead-technology-creates-new-set-of-problems-a-perspective-from-one-electrophysiologist","status":"publish","type":"post","link":"https:\/\/blogs.nejm.org\/cardioexchange\/2012\/07\/19\/new-icd-lead-technology-creates-new-set-of-problems-a-perspective-from-one-electrophysiologist\/","title":{"rendered":"New ICD Lead Technology Creates New Set of Problems: A Perspective From One Electrophysiologist"},"content":{"rendered":"

CardioExchange welcomes this guest post from Edward J. Schloss, MD, the medical director of cardiac electrophysiology at Christ Hospital in Cincinnati, OH.<\/em><\/p>\n

Why I Don\u2019t Like DF-4: A Personal Perspective<\/strong><\/p>\n

Since the first human implantable cardioverter defibrillator (ICD) implant in 1980, there have been a wealth of technological advances that have allowed these devices to become a standard therapy in the treatment of patients at risk for sudden cardiac arrest.\u00a0 Some of these, such as nonthoracotomy lead systems and biphasic waveforms, have revolutionized the industry.\u00a0 Others, such as downsized lead caliber, have added risk without clear benefits.<\/p>\n

The DF-4 ICD lead is one of the latest technologies to be approved in cardiac rhythm management.\u00a0 DF-4 refers to the type of pulse generator connector on these leads.\u00a0 All three major U.S. ICD vendors have FDA-approved DF-4 ICD leads, and these have been generally well received by the implanting physician community.\u00a0 In this perspective, I endeavor to show that it may be appropriate to temper this enthusiasm.<\/p>\n

Historical Background and Lead Design<\/strong><\/p>\n

Early ICDs required open-chest surgery to implant and were offered only to high-risk cardiac arrest survivors.\u00a0 In the early 1990s, transvenous lead ICD systems eliminated the need for thoracotomy or sternotomy. Soon thereafter, these leads were coupled with downsized ICD generators and advanced shock waveforms resulting in significant improvements in implant safety and success.\u00a0 As device indications expanded into primary prevention after the MADIT and SCD-HeFT trials, ICD implantation exploded in the U.S.<\/p>\n

Over the years, a variety of industry standards have evolved to connect ICD leads to pulse generators under the guidance of the International Organization for Standardization (ISO).\u00a0 For most of the modern ICD era, we have been using ICD leads that have the DF-1\/IS-1 connector.\u00a0 A representative DF-1\/IS-1 lead is shown in figure 1:<\/p>\n

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In the figure, note the pulse generator header connections are on the top right and the connection to the ventricular endocardium is in the bottom left.\u00a0 The header connectors consist of one low-voltage pacing\/sensing connector, termed IS-1, in the middle, and one or two high-voltage shock connectors, termed DF-1, alongside.\u00a0 These come together into a yoke that integrates the conductors into a single lead body as it enters the vasculature.<\/p>\n

DF-4 was designed as an independent standard, combining all conductors into a single connection to the ICD header. In 2009, the first DF-4 ICD lead was FDA approved and marketed by St. Jude Medical.\u00a0 In the U.S., Medtronic and Boston Scientific also have available DF-4 ICD leads.\u00a0 Pictured in figure 2 is a DF-4 connector above a DF-1\/IS-1 connector:<\/p>\n

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Note that the DF-4 lead has only one connection and no yoke.\u00a0 In addition, there are no plastic sealing rings on the lead connectors, as these are now integrated into the pulse generator.<\/p>\n

At implant, these lead connectors are attached to an ICD pulse generator.\u00a0 The lead body is coiled behind and closed within the device pocket as shown in figure 3.<\/p>\n

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Doctors have embraced DF-4 technology and, according to some industry personnel, adoption has exceeded expectations.\u00a0 Potential advantages to DF-4 include:<\/p>\n