Increased body mass index, age, and left atrial size are associated with altered intracardiac atrial electrograms in persistent atrial fibrillation patients

Background There are limited studies evaluating whether atrial fibrillation (AF) patients with increased BMI, age, and left atrial (LA) size have altered intracardiac electrogram (EGM) morphology. Methods We analyzed left atrial intracardiac EGMs acquired during invasive electrophysiology study in 54 patients with AF. EGM correlations were assessed among AF risk factors including age, left atrial size, and BMI. Results BMI correlated positively with DF ( r 2 = 0.17, p = 0.009) and MP ( r 2 = 0.16, p = 0.01) with dominant frequency (DF) and mean spectral profile (MP) greater among obese individuals. Age was negatively associated with mean amplitude ( r 2 = 0.42, p < 0.001) and width ( r 2 = 0.32, p < 0.001); age was positively correlated with MP ( r 2 = 0.24, p < 0.001). LA size was negatively correlated with mean amplitude (r 2 = 0.18, p = 0.03) and width ( r 2 = 0.23, p = 0.01); LA size was positively correlated with DF ( r 2 = 0.22, p = 0.01) and MP ( r 2 = 0.23, p = 0.01). Mean amplitude and width were decreased among subjects with a severely enlarged LA; DF and MP were increased in those with severely enlarged LA. The associations with BMI and LA size remained significant in multiple regression models that included age, male gender, time since AF diagnosis, and LVEF. Conclusions EGM morphology of AF patients with increased BMI, older age, and an enlarged LA possessed decreased amplitude and decreased width and increased DF and MP. These findings suggest that atrial remodeling due to increased age, LA size, and BMI is associated with differences in local atrial activation, decreased refractoriness, and more heterogeneous activation. These novel findings point out clinical risk factors for atrial fibrillation that may affect electrogram characteristics.