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Clinical Efficacy and Safety of an Implantable Cardioverter-Defibrillator Lead with a Floating Atrial Sensing Dipole


  • The study was supported by BIOTRONIK SE & Co KG (Woermannkehre 1, D-12359 Berlin, Germany). The corresponding author participated in the BIOTRONIK International Fellows Program 10/2010-06/2011.

  • Conflict of Interest: None declared.

Address for reprints: Erdal Safak, M.D., Charité Campus Benjamin Franklin, Medical Clinic II, Hindenburgdamm 30, 12200 Berlin, Germany. Fax: 00493084454648; e-mail:



The concept of a single-lead implantable cardioverter-defibrillator (ICD), with a floating dipole, has been proven safe and functional.

Methods and Results

The studied active-fixation, steroid-eluting lead (Linoxsmart S DX, BIOTRONIK SE & Co KG, Berlin, Germany) is one French thinner than its predecessor and coated with lubricious SilGlide to improve lead handling. A dedicated ICD device has a self-adaptive atrial input stage including a fourfold amplifier. The amplification, filtering, and adapted atrial input stage are located in the Lumax 540 VR-T DX (BIOTRONIK). The Linoxsmart S DX ICD lead delivers only the signal. The lead was evaluated during implantation; at predischarge; and 1-, 3-, and 6-month follow-up examinations. The primary endpoint (efficacy) was the rate of appropriate atrial sensing tests. The secondary endpoint (safety) was freedom from lead-related invasive reinterventions. Both safety and efficacy were expected to be significantly higher than 90%.

The study enrolled 116 patients at 25 clinical sites. Skin-to-skin operation time was 52.4 ± 26.2 minutes. The investigators graded lead insertion as “easy” in 87% of patients. Mean P-wave amplitudes (preamplified) varied from 5.0 to 6.1 mV in different body positions. Both primary and secondary endpoints were met, as 93.8% (364/388; P = 0.005) of specific sensing tests indicated appropriate atrial sensing, and 94.8% (110/116; P = 0.048) of patients were free from reinterventions (lead dislodgement). Analysis of arrhythmia episodes stored in ICDs and elective 24-hour Holter electrocardiogram tests raised no concerns about lead functionality.


The studied ICD lead with a floating atrial sensing dipole met the predefined safety expectation and demonstrated appropriate atrial sensing performance.