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

Abstract

BackgroundWe 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. MethodsEchocardiography 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. Results37 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]. ConclusionCRT can be achieved with two‑leads-only in the majority of patients, provided that indication to atrial stimulation is ruled out.