What happened
His/LBB pacing noninferior to BiV for LVESV reduction (35% vs 34%).
Its licence doesn't allow us to show a copy here.
Electrophysiology · Copenhagen University Hospital
What do you think the place is for CSP in heart failure patients who are candidates for CRT?
HIS Alternative II co-authorElectrophysiology · Copenhagen University Hospital
Looking forward to discussing HIS Alternative II with this community.
HIS Alternative II co-authorWhy the trial, key points, tables, limitations, PICO, abstract, media & sources
Why the trial?
His bundle pacing offers more physiological ventricular activation than biventricular pacing, but randomised evidence in heart failure patients needing resynchronisation is limited to small studies. HIS Alternative II compared the two strategies head-to-head.
Does conduction system pacing (CSP-CRT) improve left ventricular end-systolic volume compared to biventricular pacing in patients with symptomatic heart failure, LVEF ≤35%, and LBBB?
| Outcome | His/LBB | BiV |
|---|---|---|
| Relative LVESV reduction at 6 months | -35% +/- 22% | -34% +/- 22% |
| Primary endpoint · difference 0.9% (95% CI -6.0 to 7.8); noninferior (P<0.01), not superior (P=0.80) | ||
| LVEF increase | +14% +/- 8% | +14% +/- 9% |
| Secondary outcome · no significant difference | ||
| 6-minute walk distance change | +37 +/- 53 m | +24 +/- 48 m |
| Secondary outcome · improvement in both arms | ||
Design limitations
The primary endpoint is echocardiographic remodeling over only 6 months, and 15 patients (15%) in the conduction-system-pacing arm crossed over to biventricular pacing at implantation (vs 1 the other way).
Statistical certainty
Small trial (150 patients); adverse-event rates beyond crossover are not reported in the record.
Does conduction system pacing (CSP-CRT) improve left ventricular end-systolic volume compared to biventricular pacing in patients with symptomatic heart failure, LVEF ≤35%, and LBBB?
In patients with HFrEF and LBBB, conduction system pacing is noninferior to biventricular pacing for improving left ventricular end-systolic volume and functional outcomes.
this is an interesting first take. A well done study but limited by duration of follow up and sample size. It does seem to indicate when the procedure is well done, actually both procedures well done there may not be that much difference between both techniques.
Expert reaction
JACC Clinical Electrophysiology · ESC Congress 2026
0 experts have reacted so far. We show the split once 3 have.
Expert labels are toward HIS Alternative II's result, from named public quotes (n=0). As of Oct 31, 2026.
Captured external expert commentary on this trial, strongest first. Original sources are linked where available.
The HIS Alternative II trial compared His bundle pacing versus biventricular pacing in patients with heart failure, presented by Michael Vinther.
“These studies have shown excellent and similar or even better responses with CSP-CRT compared to BiV-CRT and comparing our results to some of the latest European studies (CSP-Sync and Left Bundle CRT) the improvements in the patients randomized to CSP-CRT were almost identical regarding LVEF and...”
His/LBB pacing was noninferior to biventricular pacing for LVESV reduction (35% vs 34%).
BACKGROUND: Cardiac resynchronization therapy (CRT) in patients with symptomatic heart failure and left bundle branch block (LBBB) can be achieved with biventricular pacing (BIV-CRT) or conduction system pacing (CSP-CRT). OBJECTIVES: The present study examined if CSP-CRT was feasible and noninferior to BIV-CRT. METHODS: A total of 150 patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35%, and LBBB (Strauss criteria) were included. Patients were randomized 1:2 to either BiV-CRT or CSP-CRT (HIS-CRT or LBB-CRT) and followed for 6 months. The primary endpoint was the relative change in left ventricular end-systolic volume (LVESV). Two patients withdrew their consent before implant. RESULTS: At implantation, 15 patients (15 %) crossed over from the CSP-CRT group to the BiV-CRT group and 1 patient crossed over from BiV-CRT to the CSP-CRT group. Accordingly, 85 patients (57 %) were treated with CSP-CRT (26 His-CRT, 59 patients LBB-CRT) and 63 patients (43 %) with BiV-CRT. For the primary endpoint, intention-to-treat 6-month follow-up LVESV decreased by 35% ± 22% with CSP-CRT vs 34% ± 22% with BiV-CRT (between-group differences 0.9%, 95% CI: -6.0% to 7.8%; P < 0.01 for noninferiority, P = 0.80 for superiority). Furthermore, LVEF increased by 14% ± 8% with CSP-CRT vs 14% ± 9% with BiV-CRT (P = NS). QRS duration shortening (-31 ± 22 ms vs -31 ± 21 ms), 6-min walking distance increase (37 ± 53 m vs 24 ± 48 m), Minnesota Living with Heart Failure score reduction (-16 ± 18 vs -13 ± 15), NYHA functional class improvement (-0.6 ± 0.6 vs -0.6 ± 0.7), and N-terminal pro-B-type natriuretic peptide reductions (-72 ± 152 pmol/l vs -110 ± 116 pmol/l) were similar between groups. CONCLUSIONS: In heart failure patients with LBBB, CSP-CRT was noninferior to BiV-CRT in reducing LVESV and both treatment modalities provided similar and excellent improvements in LVEF, QRS duration, heart failure symptoms, and functional capacity.
Vinther et al. (2026) conducted an RCT in Heart failure with reduced ejection fraction and typical left bundle branch block. Conduction-system pacing (His bundle or left bundle branch) vs. Biventricular pacing was evaluated on Change in left ventricular end-systolic volume. Conduction-system pacing (His/LBB) was noninferior to biventricular pacing for reducing left ventricular end-systolic volume (35% vs 34% reduction) in patients with heart failure and typical LBBB.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: