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SyncAV PMTDevices & ArrhythmiasOpen Access
Clinical benefit of dynamic atrioventricular optimisation during cardiac resynchronisation therapy
Key result
SyncAV matches fixed AV intervals overall but reduces mortality and HF hospitalizations when PR ≥185 ms.
Why the trial?
Fixed atrioventricular delays may leave cardiac resynchronisation suboptimal as physiology changes beat to beat. SyncAV PMT asked whether continuous dynamic AV optimisation during CRT translates into measurable clinical benefit.
Does dynamic triple fusion pacing with SyncAV improve outcomes compared to a conventional fixed AV interval in patients receiving cardiac resynchronisation therapy?
Population
Patients receiving cardiac resynchronisation therapy; sample size not reported
Comparison
SyncAV dynamic AV optimisation vs conventional fixed AV interval
Design
Randomized trial; blinding, centres and other design details not reported
Authors
Discussion
Key questions
No takes yet. Share an insight, caveat, or question.
Key expert perspectives
Captured external expert commentary on this trial, strongest first. Original sources are linked where available.
SyncAV PMT randomized 1,288 CRT recipients with LBBB to dynamic AV delay optimization (SyncAV) versus conventional fixed AV programming. The primary endpoint of 12-month LVESV reduction was not significantly different between groups overall. In a prespecified subgroup with PR interval ≥185 ms, SyncAV showed benefits in mortality, heart failure hospitalisations, persistent AF, and echocardiographic CRT response. Early expert reaction notes that improved electrical resynchronization did not translate to better global outcomes, but the subgroup finding is considered physiologically compelling and hypothesis-generating.
3 takes classified by contention axis so far — the map appears as more land.
“In 1,288 patients with LBBB, LVEF ≤35% and QRS ≥120 ms, SyncAV improved electrical resynchronization, but did not improve the primary remodeling endpoint versus fixed AV programming: LVESV reduction at 12 months: −45 vs -47 mL, p=0.054; CRT responders: 75.2% vs 79.4%, p=0.16. Overall mortality and HF hospitalization were also similar. The intriguing signal came from patients with PR ≥185 ms, where SyncAV appeared to improve several clinical composites. This subgroup finding is hypothesis generating, but physiologically compelling: patients with longer AV conduction may have more room to benefit from dynamic fusion pacing. A useful reminder that in CRT, better electrical resynchronization does not automatically translate into better global outcomes, but patient selection may matter more than the algorithm itself.”
“SyncAV trial: Automatic dynamic AV delay optimization did not significantly improve the reduction in 12-month LVESV compared with standard fixed programming in patients with LBBB and HF.”
“Dr. Niraj Varma and Dr. C. Michael Gibson discuss the SyncAV trial: No significant difference in the reduction of 12-month LVESV between dynamic AV delay optimization vs. fixed programming among patients with LBBB and HF on GDMT.”
Implication
SyncAV does not improve primary CRT remodeling endpoints versus fixed AV intervals; leaves open a mortality benefit in the PR ≥185 ms subgroup for prospective confirmation.
Key Points
- To evaluate the clinical efficacy of dynamic triple fusion pacing using SyncAV compared to conventional fixed atrioventricular intervals in patients receiving cardiac resynchronisation therapy.
- Assessed dynamic triple fusion pacing with SyncAV against conventional fixed atrioventricular interval programming in cardiac resynchronisation therapy patients.
- Overall cardiac resynchronisation therapy efficacy remained robust and similar between the dynamic SyncAV and conventional fixed atrioventricular interval arms.
- In patients with baseline PR intervals ≥185 ms, SyncAV pacing reduced all-cause mortality, heart failure hospitalisations, persistent atrial fibrillation, and negative echocardiographic response compared to fixed intervals.
Evidence details
Limitations & tradeoffs
Statistical certainty
No numeric outcome data, sample size, or follow-up duration are reported in the record.
Subgroup caution
Mortality, heart-failure hospitalisation, AF and echo benefits were reported only in the PR ≥185 ms subgroup; overall CRT efficacy was similar between arms.
Structured PICO
Does dynamic triple fusion pacing with SyncAV improve outcomes compared to a conventional fixed AV interval in patients receiving cardiac resynchronisation therapy?
P
Population
Patients receiving cardiac resynchronisation therapy.
I
Intervention
Dynamic triple fusion pacing with SyncAV
C
Comparator
Conventional fixed AV interval
O
Outcome
Overall CRT efficacy
While overall CRT efficacy was similar, dynamic AV optimization with SyncAV provided significant clinical and echocardiographic benefits in the subgroup of patients with prolonged PR intervals (≥185 ms).
Cite This Study
Niraj Varma (2026) conducted an RCT in Patients receiving cardiac resynchronisation therapy. Dynamic triple fusion pacing with SyncAV vs. Conventional fixed AV interval was evaluated on Overall CRT efficacy. Dynamic triple fusion pacing with SyncAV showed similar overall CRT efficacy to a fixed AV interval, but reduced mortality and heart failure hospitalizations in patients with PR intervals ≥185 ms.