A porcine model of early atrial fibrillation using a custom-built, radio transmission-controlled pacemaker

• We present a pig model of early atrial fibrillation using a custom-built pacemaker.
• The spontaneous atrial rhythm was interrogated telemetrically in conscious animals.
• We found atrial structural remodeling and increased stability of atrial fibrillation.
• Evidence of left ventricular dysfunction was not present.
• Experimental arterial hypertension accelerated atrial remodeling.

Mechanisms underlying atrial remodeling toward atrial fibrillation (AF) are incompletely understood. We induced AF in 16 pigs by 6 weeks of rapid atrial pacing (RAP, 600 bpm) using a custom-built, telemetrically controlled pacemaker. AF evolution was monitored three times per week telemetrically in unstressed, conscious animals. We established a dose–response relationship between RAP duration and occurrence of sustained AF > 60 minutes. Left atrial (LA) dilatation was present already at 2 weeks of RAP. There was no evidence of left ventricular heart failure after 6 weeks of RAP. As a proof-of-principle, arterial hypertension was induced in 5/16 animals by implanting desoxycorticosterone acetate (DOCA, an aldosterone-analog) subcutaneously to accelerate atrial remodeling. RAP + DOCA resulted in increased AF stability with earlier onset of sustained AF and accelerated anatomical atrial remodeling with more pronounced LA dilatation. This novel porcine model can serve to characterize effects of maladaptive stimuli or protective interventions specifically during early AF.