Chronic performance of an active fixation coronary sinus lead.

Background: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in appropriately selected patients with heart failure. Optimal left ventricular (LV) lead placement is useful in enhancing response from CRT. Three significant obstacles to LV lead placement are patient-specific variations in coronary venous anatomy, phrenic nerve stimulation, and a significant rate of LV lead dislodgement or microdislodgement.

Objective: The primary objective of this study was to determine the safety and effectiveness of the Medtronic StarFix active fixation LV lead. Secondary objectives evaluated implant success, lead placement and procedure time, lead handling and lobe deployment, additional electrical performance, and all adverse events reported in the study.

Methods: There were 441 patients enrolled in this multicenter study. Standard cardiac resynchronization therapy (CRT) inclusion criteria were used. Patients were followed up for a mean of 23 months. Implant data, success with CRT, LV lead performance, clinical outcomes, and experience with LV lead revisions were prospectively evaluated.

Results: The mean LV stimulation threshold at implant was 1.3 +/- 1 volts and was stable over time. Sensing was also excellent. In 96.3% of the implantations in this study, the physician was able to place the lead in a nonanterior position. Extracardiac (phrenic nerve) stimulation required invasive intervention in 11 subjects (2.5%). Only 3 dislodgements (0.7%) were observed. Two occurred in the first 5 implants and were attributed to inadequate engagement of the venous subbranch.

Conclusion: The Medtronic 4195 is safe and highly efficacious. It affords the physician more choices in lead placement location and has a remarkably low dislodgement rate.