Two-Lead DX-based versus conventional three-Lead CRT-D: a single centre experience

Background

Cardiac resynchronization therapy with defibrillator (CRT-D) is a well-established therapy for patients with heart failure (HF) and intraventricular conduction delays, but a non-negligible risk of infection and of lead functionality loss overtime is related to intravascular hardware.

The novel DX system enables atrial sensing through a floating dipole integrated into the ICD lead, reducing the intravascular burden.

Purpose

In this prospective nonrandomized study, we aimed to evaluate the safety and efficacy of a two-lead DX-based CRT system compared to a conventional three-lead (3L) CRT-D system.

Methods

A total of 210 patients meeting CRT indications and no signs of sick sinus syndrome (SSS) (baseline HR ≥ 45 bpm, or at least 85 bpm at 6 minute walking test ) were enrolled. Patients were assigned to either the CRT-DX (97/210) or conventional 3L CRT-D group (113/210). The clinical endpoint was a composite freedom from cardiovascular death, HF hospitalization, or new-onset atrial fibrillation (AF) while the ecocardiographic response was defined as left ventricular end-systolic volume (LVESV) reduction (using both cut offs of ≥15% or ≥ 9.3% LVESV reduction available in literature)

Results

After a mean follow-up of 46.5 ± 1.9 months, both groups had comparable clinical outcomes with a mean 64% freedom from composite clinical endpoint (p=ns).

CRT delivery was high in both groups (mean 95%) and it was paralleled by an eleveted mean ecocardiographic response of 75 % (9.3 % cut-off) and 71 % (9.3% cut-off) and a mean LVESV reduction of 47 mL by the end of follow-up.

Of note, CRT-DX patients exhibited higher atrial sensing amplitudes and no significant differences in loss of lead function. 3/113 atrial displacements occurred in the 3L CRT-D group while 1/97 CRT-DX patient developed atrial undersensing (requiring revision to enable CRT) and 1/97 developed SSS (requiring upgrade to 3L-CRT-D at the time of generator replacement).

Conclusions

In conclusion the CRT-DX system provides equivalent clinical and echocardiographic benefits compared to conventional CRT-D in patients without an indication for atrial pacing in the long term.

This study supports the use of the DX system as a safe and effective alternative in the majority of CRT recipients.Patients' selection