Key result
Switching to SyncAV narrows QRS by ~14 ms but shows no clinical benefit over de novo use.
Why the study?
Individualized AV-synchronous pacing with the SyncAV algorithm may provide hemodynamic advantages in CRT patients, but the long-term effects of switching from a fixed AV delay to SyncAV remain unclear.
Does switching from a fixed AV delay to the SyncAV algorithm reduce the composite of all-cause mortality and hospitalizations and improve QRS and echocardiographic parameters in CRT patients?
Observational (n=62)
Does switching from a fixed AV delay to the SyncAV algorithm reduce the composite of all-cause mortality and hospitalizations and improve QRS and echocardiographic parameters in CRT patients?
Switching CRT patients from a fixed AV delay to the SyncAV algorithm shortened QRS duration over 12 months, but did not result in significant left ventricular reverse remodeling or clinical benefit.
Should not yet change routine CRT programming to late SyncAV activation; leaves open whether acute electrical resynchronization translates to hard clinical outcomes in randomized trials.
Introduction Optimizing atrioventricular (AV) timing is a key factor in maximizing cardiac resynchronization therapy (CRT) benefits. While initial AV programming may be fixed, individualized AV-synchronous pacing with the SyncAV algorithm could provide additional hemodynamic advantages. The long-term effects of switching from fixed AV delay to SyncAV remain unclear. Aim To compare clinical outcomes, echocardiographic and electrocardiographic changes of CRT patients initially programmed with fixed AV delay and subsequently switched to SyncAV. Methods This was a prospective follow-up trials that include patients with a CRT programmed with fixed AV delay for 12 months who underwent switch to SyncAV algorithm. Primary endpoints included the composite of all-cause mortality and hospitalizations. Secondary endpoints included changes in QRS and echocardiographic parameters. Results We included 62 patients (52.9% male), with a mean age of 68.9± 9.6 years. 72.9% of the patients had dilated cardiomyopathy and 78.6% were on functional class II of the NYHA. At baseline, the mean left ventricular ejection fraction (LVEF) was 48.5%, the mean intrinsic QRS was 157 ms and the median percentage of biventricular pacing (BIV) was 99%. The baseline heart failure medications and comorbidities are in Table 1. After 12 months follow up, the primary endpoint occurred in 13 patients. When comparing our patients with those who had CRT with SyncAV activated from device implantation, no differences in clinical events were observed, suggesting that the SyncAV algorithm is not associated with clinical benefit in CRT patients, regardless of the duration of algorithm activation- Graph 1. Considering the secondary endpoints, after 12 months of SyncAV activation, median intrinsic QRS duration was reduced by 7 ms relative to baseline values and median QRS duration in pacing was reduced by 14 ms. The SyncAV algorithm was associated with modest improvement in LVEF (+ 4.1%) and index left ventricular end systolic volume (1.1 mL/m2)- Table 2. Conclusion Switching to the SyncAV algorithm in CRT patients previously on fixed AV delay led to additional QRS shortening. However, this did not translate into significant left ventricular reverse remodelling nor clinical benefit at 1 year.Endpoints
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Esteves et al. (2026) conducted an observational in Cardiac resynchronization therapy (CRT) patients (72.9% dilated cardiomyopathy) (n=62). Switch from fixed AV delay to SyncAV algorithm vs. Baseline fixed AV delay / CRT with SyncAV activated from device implantation was evaluated on Composite of all-cause mortality and hospitalizations. Switching CRT patients from fixed AV delay to SyncAV shortened paced QRS by 14 ms, with 13/62 (21.0%) experiencing death or hospitalization at 12 months and no clinical benefit vs de novo SyncAV.
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