Adverse outcomes due to atrioventricular synchrony loss induced by temporary VVI pacing in patients with pre-existing DDD stimulation: insights from a device recall scenario

Temporary reprogramming of dual-chamber (DDD) pacemakers to non-synchronous ventricular modes (VVI/VVIR) may be required in selected clinical scenarios, but short-term consequences of abrupt atrioventricular (AV) synchrony loss remain incompletely characterized.

Leveraging a unique natural experiment, this study aimed to quantify the clinical and echocardiographic consequences of temporary VVI/VVIR pacing in patients in sinus rhythm chronically adapted to DDD stimulation.

In this prospective observational study, 93 patients (79.9 ± 16.0 years; 63.4% AV block) with recalled DDD pacemakers were reprogrammed to VVI/VVIR for 6 months, followed by DDD restoration. Serial assessments included echocardiography, BNP, and 6-min walk test. Primary endpoints were changes in left ventricular ejection fraction (LVEF) and heart failure (HF) hospitalizations; secondary endpoints included echocardiographic remodelling parameters, functional capacity, quality of life, and atrial fibrillation. Clinical events were tracked for 12 months. Ventricular pacing remained >88% throughout. During the VVI/VVIR period, HF hospitalizations increased compared with the subsequent DDD restoration period (22.6% vs. 6.7%, P < 0.001). This was accompanied by adverse echocardiographic remodelling, a decline in LVEF from 57.3% to 53.0% (P < 0.001), and a marked BNP increase from 155 to 260 pg/mL (P < 0.001). After DDD restoration, clinical and structural recovery was incomplete: LVEF improved to 54.8% and BNP decreased to 210 pg/mL, but both remained significantly worse than baseline (P < 0.05).

Temporary loss of AV synchrony in chronically DDD-paced patients was associated with rapid, severe, and only partially reversible clinical and echocardiographic deterioration. These findings underscore that continuous AV synchrony is a critical determinant of clinical stability.