Less is more: Can we achieve cardiac resynchronization with 2 leads only?

Background: We compared clinical and technical outcome of CRT recipients treated either with a conventional 3‑leads (3L) CRTD or with the new 2‑leads (DX) CRTD that enables atrial signal detection by a floating dipole built on a pentafilar RV lead.

Methods: Echocardiography and cardiopulmonary exercise tests were repeated either before CRTD implantation and between 6 and 12 months follow up in consecutively implanted patients who had a resting heart rate>40bpm at maximum tolerated beta-blocker dosage. HF status, reverse LV remodeling, exercise tolerance and chronotropic incompetence were assessed at 12 months FU. Device diagnostics were obtained twice yearly until December 2016.

Results: 37 patients aged 66 (58-73) years were consecutively implanted in 2013-2014 according to current guidelines, 25 with a 3L CRTD and 12 with a DX CRTD. Beta-blocker dosage was similar, and no difference between the 2 groups was observed in terms of NYHA class improvement, LV reverse remodeling, peak cardiopulmonary performance and presence of chronotropic incompetence at 12 months follow up. There was no difference in: amount delivered CRT; occurrence of VT/VF; occurrence of AT/AF. No patients developed need of atrial stimulation at 3-years FU. Atrial undersensing never occurred in any patient, whereas Far-field R-wave oversensing was more common in 3L patient than in DX patients (8/25 vs none, P<0.05). P wave amplitude was greater in DX vs 3L patients [5.1(3.7-9.2) vs 2.9(2-3.9) mV, P<0.01].

Conclusion: CRT can be achieved with two‑leads-only in the majority of patients, provided that indication to atrial stimulation is ruled out.