Atrial antitachycardia pacing and atrial remodeling: A substudy of the international, randomized MINERVA trial

Atrial tachycardia (AT) and atrial fibrillation (AF) are common in pacemaker patients and are associated with bad prognoses.

The purpose of this study was to evaluate atrial antitachycardia pacing impact on AT/AF-induced atrial remodeling, measured by early recurrence of AT/AF (ERAF) and by change in left atrial diameter (LAD), and to evaluate the impact of AT/AF duration on ERAF incidence.

Pacemaker patients were randomized to dual-chamber pacing (Control DDDR: 385 patients), managed ventricular pacing (MVP: 398 patients), or atrial antitachycardia pacing plus MVP (DDDRP+MVP: 383 patients). LAD change, estimated by echocardiography, was considered significant if the relative difference between baseline and 24-month measurements was >10%.

At median follow-up of 34 months, ERAF incidence was significantly lower in the DDDRP+MVP arm for all AT/AF durations, in particular, ERAF followed AT/AF longer than 3 hours in 53% cases in Control DDDR, in 51% cases in MVP, and in 39% cases in DDDRP+MVP (P <.001 vs other groups). ERAF incidence showed a U-shaped pattern when evaluated as a function of previous AT/AF duration, decreasing for durations from 5 minutes to 12 hours and increasing for longer durations. Among patients with significant LAD change, the proportion of patients with a reduction in LAD was 35% in Control DDDR, 37% in MVP, and 70% in DDDRP+MVP (P <.05 vs other groups).

Our data suggest that atrial electrical remodeling becomes important after about 12 hours of continuous arrhythmia. Compared to DDDR or MVP, DDDRP+MVP reduces ERAF and favors LAD reduction, suggesting that atrial antitachycardia pacing may reverse electrical and mechanical remodeling.