Clinical experience and procedural outcomes associated with the DF4 implantable cardioverter defibrillator system: the SJ4 postapproval study

Abstract

Background: Current implantable cardioverter defibrillators (ICDs) employ two or three low- and high-voltage lead connectors, adding complexity and bulk, sometimes resulting in incorrect connections and adverse events. The SJ4 study evaluates the performance of a novel integrated single-lead DF4 connection system by characterizing lead measurements, handling characteristics, and outcomes.

Methods: Patients with standard guidelines-based ICD indications were enrolled and implanted with a St. Jude Medical™ DF4 system (St. Jude Medical, Sylmar, CA, USA; right ventricular high-voltage DF4 lead models 7120Q, 7121Q, 7122Q, or 7170Q with compatible ICD). Device electrical measurements, handling characteristics, and any adverse events were collected at implant and during each scheduled 6-month follow-up.

Results: Among 1,701 patients (65 ± 13 years, 72% male, left ventricular ejection fraction 29 ± 12%) enrolled at 58 centers, there were 1,697 successful implants (99.8% implant success; ICD; n = 999, cardiac resynchronization therapy-defibrillator n = 698). Implanting physicians reported that implantation of the DF4 lead was normal or easier than normal in 94% of cases with successful implant. These patients have been followed for 1.7 ± 0.5 years with a maximum follow-up of 2.5 years. The complication rate was 0.017 per patient year of follow-up (95% confidence interval: 0.013-0.023), which included abnormal defibrillation impedance, elevated pacing thresholds, failure to detect ventricular tachycardia/ventricular fibrillation, lead dislodgement, lead fracture, loss of capture, and lead perforation. There were no set screw-related complications at implant or during follow-up.

Conclusion: The DF4 system overall performed very well with few complications at implant and in follow-up.

Keywords: DF4; connectors; implantable cardioverter defibrillator leads.