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Updated: Jul 14, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
Do small (6.6 Fr.) active and passive fixation defibrillation leads perform as well as larger sized leads? A
Bernhard Küpper1, Raymond Yee, Gilles O'Hara
1Schüchtermann Klinik, Bad Rothenfelde, Germany. b.kuepper@elisabeth-essen.de
Aims:
The 6.6 Fr. Sprint Fidelis lead family may allow multiple lead implantation procedures with reduced risk of venous obstruction.
Methods And Results:
Two prospective, historically controlled, multi-centre studies were conducted in Europe (80 patients) and Canada (79 patients). The purpose was to assess the ventricular lead-related adverse events (LRAEs) and performance of the small Models 6948 and 6949 defibrillation leads, respectively, in patients with a standard indication for an ICD implant. Safety was assessed by demonstrating equivalence of the LRAE free rate at 1 month to comparable but larger leads (Models 6942, 6943, 6944, 6947and 4074). Seventy-five of 80 patients with a 6948 lead (93.8%) remained free of LRAEs. Seventy-four out of 79 patients (93.7%) with the 6949 lead remained free of LRAEs. The 95% lower confidence bounds were above the critical difference limits. Thus, safety of the Sprint Fidelis((R)) leads is similar to that of larger leads. Electrical performance through 1-month follow-up proved to be acceptable in comparison with other established leads.
Conclusion:
These multi-centre studies confirm that smaller defibrillation leads offer similar safety and efficacy features to widely used larger leads; they have low LRAE rates and defibrillation thresholds, while providing the advantage of a smaller introducer size and reduced venous obstruction.

