His-Alternative II — Direct His/LBB Pacing as an Alternative to Biventricular Pacing in Patients With Symptomatic Heart Failure Despite Optimal Medical Treatment and an ECG With a Typical Left Bundle Branch Block Pattern

doi:10.1016/j.jacep.2026.08.008

HIS Alternative II

Patient / Population Intervention / Exposure Comparison Outcome

In 148 patients with HFrEF and left bundle branch block, conduction-system pacing was non-inferior to biventricular pacing for the change in LV end-systolic volume at 6 months.

N

148patients

Design

Investigator-initiated, multicentre (Rigshospitalet, Copenhagen; Imperial College Healthcare NHS Trust, London), randomised 1:2 (biventricular CRT : conduction-system-pacing CRT) non-inferiority trial; patients and echocardiography/6-minute-walk assessors blinded; in the CSP arm His-bundle pacing is attempted first, then left bundle branch pacing, with a coronary-sinus LV lead as bail-out (and vice versa in the control arm); 6-month follow-up; enrolment June 2020 to February 2026.

Endpoint

Change in left ventricular end-systolic volume by echocardiography at 6 months (non-inferiority versus biventricular CRT); the registry also lists the success rate of His-bundle or LBB lead implantation with LBBB correction as a co-primary

Relevance

2Important — one of several pillars.

ResultThe relative fall in left ventricular end-systolic volume at 6 months differed by 0.9 percentage points (95% CI −6.9 to 8.7; P = 0.003 for non-inferiority, P = 0.8 for superiority); on-treatment 2.7 points (−4.6 to 10.0; P < 0.001 for non-inferiority). QRS duration, ejection fraction, NT-proBNP, NYHA class, quality of life and walking distance improved comparably, and the safety profiles were similar.

Vinther M, Philbert BT, Risum N, et al. J Am Coll Cardiol EP. 2026; published online 31 August. 10.1016/j.jacep.2026.08.008

Discussion & critique

Pacing the conduction system rather than the free wall matched biventricular CRT on reverse remodelling at six months, with the same electrical and clinical gains and no safety penalty — the first randomised comparison to say so in patients selected by Strauss criteria. It is 148 patients at two centres with a surrogate endpoint and a 10% margin, so what is shown is that the strategies are interchangeable for the ventricle, not that either changes outcomes. The investigators say the same: promising, and waiting on larger trials with longer follow-up.