Long‐Term Performance of Single‐Chamber Atrioventricular‐Synchronous Leadless Pacing: Results From 4 Years of Serial Follow‐up

ABSTRACT Introduction Micra AV enables atrioventricular (AV)–synchronous pacing by sensing atrial mechanical contraction (A4) using device's accelerometer. Short‐term studies showed good AV synchrony (AVS), but long‐term data are lacking. Methods Within the OPTIVALL cohort, we identified patients implanted with a first‐generation Micra AV (June 2020–February 2024) who remained in sinus rhythm and programmed in VDD for ≥ 1 year. Device‐derived AVS was collected annually (tracking index and total AVS = AM‐VP + AM‐VS) up to 4 years. A4 amplitude was recorded at each visit. A subgroup underwent 24‐h Holter‐ECG to assess ambulatory AVS at long‐term follow‐up. Atrial sensing had been optimized early after implant with no further adjustment at follow‐up. Results Of 54 implanted patients, 44 met inclusion criteria. Median (IQR) total AVS remained stable over time: 90.6% (85.4%–93.6%), 90.6% (83.1%–92.1%), 89.2% (84.3%–92.2%), and 89.3% (86.2%–91.6%) at 1, 2, 3, and 4 years, respectively ( p = 0.789). Median (IQR) tracking index was 94.3% (88.9%–97.1%), 93.0% (85.0%–98.0%), 90.2% (84.4%–98.0%), and 90.0% (87.0%–93.9%) ( p = 0.059). Median (IQR) A4 signal amplitude was 3.1 (2.0–5.1), 5.1 (2.1–5.1), 3.7 (1.9–5.1), and 5.1 (2.5–5.1) m/s 2 ( p = 0.993). In 20 patients with 24‐h Holter‐ECG at 2.7 ± 1.1 years, ambulatory AVS was 85.5% (80.0%–90.7%) and was comparable to the 3‐month value (87.9% (76.8%–93.1%); p = 0.811). Conclusions When atrial sensing is optimized early, Micra AV can provide high and stable AV‐synchronous pacing for up to 4 years, with preserved A4 signal amplitude.