Mapping Atrial Fibrillation Drivers in Explanted Hearts

Detailed approaches for recovering explanted human hearts and functional and structural imaging of the atria were described previously [6 (link),12 (link)]. Intact explanted human donor hearts (n = 7, 47 ± 14 y.o., two females) with AF history and/or cardiac co-morbidities were obtained from Lifeline of Ohio Organ Procurement Organization (table 1). The Institutional Review Board defined the study on samples from deceased donors as Not Human Subjects Research. The entire atria were isolated, coronary perfused, immobilized with blebbistatin and stained with the voltage-sensitive dye di-4ANDBQBS for near-infrared optical mapping (UltimaL CMOS camera, SciMedia, Japan) [4 (link),6 (link)]. Induction of AF by burst pacing (2–10 s) from the superior RA and/or posterior LA was attempted in all hearts. AF drivers were defined as localized sites with the most repetitive and recurrent re-entrant pattern that led to neighbouring regions and had a minimum temporal stability of 30%. After the functional mapping, CE-MRI was performed using a 9.4 T Bruker BioSpin spectrometer (Ettlingen, Germany) [4 (link),6 (link)].