Aims:
Cancer patients treated with
anthracyclines are susceptible to
atrial fibrillation (AF), while the mechanisms remain unclear. Due to sudden and unpredictable features, prediction of
anthracycline-induced AF at early phase is difficult. Clinically, we tested whether
anthracycline-induced early
atrial remodeling in patients could be detected by echocardiography. Experimentally, we investigated the mechanisms of
doxorubicin-induced
atrial remodeling and AF in mice, and the protective effects of
dexrazoxane and
antioxidants. Methods and Results: Postsurgery
breast cancer patients with an
anthracycline-containing or
anthracycline exclusion regimen were recruited for echocardiography before
chemotherapy, and 3 and 6 months after
chemotherapy. Mice were injected with
doxorubicin or vehicle (5 mg/kg/week, 4 weeks), and left atrial diameter, electrical transmission, and AF inducibility were measured. Meanwhile, the level of
reactive oxygen species (ROS), activity of
antioxidant enzymes, cardiomyocyte size, vacuolization,
inflammation, and
fibrosis were also measured in mouse atria. The
therapeutic effects of
dexrazoxane and
antioxidants on
doxorubicin-induced changes in the aforementioned parameters were also determined. While ventricular parameters and functions were unchanged in
cancer patients receiving
anthracyclines before and after
chemotherapy, left atrial reservoir and conduit function were decreased at 3 months postchemotherapy versus prechemotherapy.
Doxorubicin-induced susceptibility to AF occurred in mice before onset of
ventricular dysfunction.
Doxorubicin-induced AF was via inducing structural remodeling (cardiomyocyte death, hypotrophy, and vacuolization) and
electrical remodeling (reduction and redistribution of
connexin 43) in atria, which was effectively prevented by
dexrazoxane or
antioxidants through inhibiting ROS generation or enhancing ROS elimination. Innovation and Conclusion: AF inducibility was induced after
doxorubicin injection, which can be inhibited by repressing the ROS level. Antioxid. Redox Signal. 37, 19-39. The Clinical Trial Registration number is PJ-KS-KY-2019-73.