Autologous Dermal Fibroblast Injections Slow Atrioventricular Conduction and Ventricular Rate in Atrial Fibrillation in Swine

BACKGROUND—Nonpharmacological ventricular rate control in atrial fibrillation (AF) without producing atrioventricular (AV) block remains a clinical challenge. We investigated the hypothesis that autologous dermal fibroblast (ADF) injection into the AV nodal area would reduce ventricular response during AF without causing AV block. METHODS AND RESULTS—Fourteen pigs underwent electrophysiology study before, immediately, and 28 days after ≈200 million cultured ADFs (n=8) or saline (n=6) were injected under electroanatomical guidance in the AV nodal area, with continuous 28-day ECG recording. In the ADF group at 28 days postinjection, there were prolongations of PR interval (after versus before130±13 versus 113±14 ms, P=0.04), of AH interval during both sinus rhythm (92±13 versus 76.8±8 ms, P